I'd probably cut Languish for Yahenni's Expertise, unless you feel you need an extra sweeper. Languish is better at being a sweeper obviously, but it's the closest card.
Maybe cut Vampire Hexmage. I never cared for Hexmage (though I don't run walkers so you may value it higher). It's double black with mediocre stats. Flesh Carver/Ophiomancer are better token producers so unless you need 3 black three drops that do that, I think Mardu strike leader is very expendable. You also have a lot of creatures in black and culling a couple I don't think will hurt you. Liliana, Death's Majesty makes creature tokens, so you aren't even losing a full dude.
Last cuts I'd be eyeing Dance of the Dead simply for being an eyesore of a card. Then probably go for the throat. You've got a decent amount of creature removal and 3 187 creatures, not sure you need GFTT.
I'll second the desire for another Goblin Welder effect not stapled to a planeswalker. I'd also be a fan of more devotion type effects since I feel mono colored strategies need more love in cube.
Not a big fan of the tri-lands. I'd rather run Vivids. This is a fundamental issue I feel with fixing in draft formats. Even dual lands are only really useful in 1 of the 10 color combinations. That's why fetch lands are top tier because even off color ones can still fix two colors for you if you get the right dual. Vivids have equal fixing as tri-lands at the cost of only being able to fix twice - which IMO is well worth the greatly increased flexibility.
So the best cycle you didn't list are the shock lands by a country mile IMO because of the basic land type interaction with fetches. I also think they are simply well designed since the drawback for entering the battlefield untapped is real and that creates a meaningful decision point during games. After that, it's a toss up for me between pains (just all around solid), temples (scry is a great mechanic on a land), and bicycles (cycling is great plus basic land types). Temples/Bicycles are even better if you also run bounce lands as the interaction between the then is synergistic.
I'd go so far as to say Flesh Carver is black's best 3 drop. Ophiomancer is better in Stax, but IMO that's it. Carver goes in pretty much any deck. It's great in control. Great in midrange. Very good in aggro mainly because it turns useless 1 drops into reach. It's splashable. It blanks removal aimed at other creatures and replaces itself if removal is cast at it (making a more dangerous threat the longer it has time to feed). Nigh unkillable to burn if you have some food for it. God forbid you get a gravecrawler/bloodghast loop going with this card. It's carrion Feeder on steroids.
After carver/ophio I think things are pretty interchangeable honestly. Run what you like. I'm still a fan of Hippie since if it doesn't get removed it wrecks havoc in ways other black 3's simply can't. Nighthawk is good value. Nothing wrong with that card at all. Geralf's Messenger is awesome in mono black, if that's a thing in your cube. I also still like bone shredder because it self bins making it easy to loop value off of. I prefer all those cards to strike leader. Drana I was not interested in testing since pure black aggro is not something I push in my cube. I'm sure it's very good there though.
Polymorph seems awful to me in cube. As a combo piece on your own creatures, it's way too much setup for questionable value. Birthing Pod this is not. And as an answer card, it's incredibly random. Also, against a lot of decks it's simply unplayable. No blue deck can possibly be this desperate for removal and the pool of better combo enablers is a mile long. Honestly, how did this card even come up in cubetutor?
My current cube is completely unrecognizable compared to the first version I built which was based on an outdated list from Tom LaPille. It was way too top heavy and basically a complete mess. This site in particular has been invaluable. As my lists are generally retro themed, I tend to rely on historical data more than current data for card choices and the archives here are quite useful for that.
I never cared for Strike Leader, and Ophiomancer I think is the better token producer, but YMMV. I know Leader is popular here and it can dodge sorcery speed removal. Nighthawk is generic value that goes in pretty much any deck that can cast it. It's the least archetype specific (calling it boring is fair), but I think you can argue it's good to run some number of cards like that since they serve as glue pieces in decks (not every card should be an archetype enabler and sometimes your deck just needs a value dude). Flesh Carver is really powerful and offers synergy being a sac outlet, so unless reducing power is the goal that one should probably stay.
I think you can easily make the argument that free sells like FOW/Daze make for bad games of magic due to the negative variance they introduce. It's one thing to play around force spike, it's entirely another to try and play around a card that your opponent can cast at any time even when tapped. Wizard's isn't going to reprint cards like that because they are not very good for the health of the game.
Cube being a largely casual format (and generally singleton), it's a lot more resilient to the effects of what these types of cards tend to introduce into the meta.
And again it comes down to context. FOW adds some negative variance. Combo decks probably benefit the most from it's inclusion, though really any deck that has a really strong play that wins if it resolves will want FOW. Does your cube need that? Are you players down with swingy games of Magic? If yes, run FOW. You'll like it and probably consider it a staple in your meta.
Have to disagree strongly on the recommendation to cut one of Memory Lapse or Remand. Who cares if their effects are similar? How many Counterspells would you run if you could? Memory Lapse and Remand are the best of countermagic behind Force of Will and Mana Drain IMO (maybe Counterspell as well). Can't see them ever leaving the Cube.
Again, it's going to be completely meta dependent. There are counter spells I'm not running that I could run. Does it change blue's identity a little? Sure. Is blue worse off? Not really, it just has a slightly different role in my cube.
If you love memory lapse, by all means run it. It's certainly good enough for small lists. But it't not essential. Very few cards actually are despite people constantly labeling things "staples". You would have to try really really (and I mean REALLY) hard to get a selection of cards together that made cube a bad experience. Half the time people argue X > Y, the difference is often negligible. If you took all the loser cards form the X > Y posts in this thread and made a cube exclusively out of them, you'd have an amazing cube. And that's why I think it's a lot more useful to answer the "this or that" question with context. Why you'd want to run card X or where it would shine. Ask yourself the question "do I need this effect or more of this effect"? Because it's a lot more useful than asking "is this card good enough" (virtually every card that gets asked about in this thread is good enough).
I also think there are better cuts than the cards you've listed. Treasure Cruise is really good. Deep Analysis is technically a 4 for 1 and flashback is just a great mechanic that is both synergistic and value simultaneously. Miscalculation is sweet because of cycle (another stellar mechanic) and Arcane Denial is the best two mana counter after real Counterspell IMO.
Repeal as a cut seems like a good recommendation. It's solid but sometimes expensive for what it does. I really like Compulsive Research and would not cut that one personally. Gilded Drake I can see being cut but it's also pretty degenerate with any sort of bounce or blink effect. I like it. I don't care for Thing in the Ice so if you want to cut a creature, that's the one I'd be looking at. Condescend or Memory Lapse if you want to shave a counter for FOW. Condescend is perfectly fine but not better than other choices IMO. Memory Lapse is basically remand and you may only need one unless Ux tempo is super popular. Memory Lapse is very good but also not something I think is essential.
Cuts in blue are hard. The pool is very deep and a lot of card choices come down to what your meta needs specifically. So we can only guide you so much. Every card listed is very playable and can be the right choice depending on your playgroup.
Gamble is cool. Obviously a bit risky since you can just two for one yourself for zero benefit, but 1 mana tutors are powerful. You really need to use this early with cards in hand so you don't bin what you get, so some advanced planning is required. Which to some extent goes against the gambling nature of the card and color. Might have made more sense as a black card.
My group was not a fan of unfun cards, so anything truly rage inducing generally got cut. The worst offender was Bribery. Land destruction and discard would be next on the list of things most don't care for. That said, outside a handful of cards I can't think of anything specific. Wildfire/Upheaval I suppose. I would not cut either under normal cube design parameters, but they also tend to get a high scoop percentage and I know at least one guy who hates playing against a deck with either (pretty sure he's hate drafted those cards).
This card is excellent. I have no idea what to cut for it though. I'm not super rigid with my gold slots, so I might just add an extra Azorius card and call it a day.
Jeskai Ascendancy seems narrow, though to be fair I've not tested it and my bias is magnified by the fact that it's three colors.
As far as running 3 color cards in general... I've been all over the field with respect to that. My last cube project was designed around shards/wedges specifically and was intended to be modular in an effort to deal with variable draft sizes. The basic idea was five 90 card modules, each focused on a wedge/shard combination. One color overlapped and so you have a bias in each module towards one color (hence 5 modules total - one for each color). Worked well when you did 3 modules or more - had a lot of variety and was very interesting since different combinations made significant meta changes - slowed things down/sped them up/altered which strategies had advantages. To some extent though you were railroaded a bit into which color combinations were viable (or at least easier to do), but the list was so synergistic within modules and across them that it was almost impossible to wind up with something unplayable even if you took the hardest color combination and forced it.
In that modular cube, despite the focus on wedge/shards, I ran no true tri-colored cards (tribrids only). Mainly due to how narrow 3 color cards are during draft. Either draft exactly deck "X", or this card doesn't make the list. In some ways, these types of cards are worse than narrow combo enablers. I'm generally not a fan of supporting 3 color gold cards. That said, there are a handful that I think you can make exceptions for without hurting your drafts too much (power level aside). Sphinx of the Steel Wind works in any cheat strategy (including tinker) where the actual mana cost on the card is largely irrelevant. Something like Progentitus can pass if Natural Order into it is a thing (though most cubes run more powerful options now). Maybe one of the Bolas Walkers or Cruel Ultimatum (though the latter is again narrow). I've always loved Lightning Angel and in a lower powered list would splash for it if I were already in two of the colors (conventional power lists probably not though).
Regardless, I don't support the idea that cubes should be forcing one card per wedge/shard even if you opt for some of these fringes exception cards. The quality drops off too much and whatever balance you think you are maintaining is being undone during the draft when the chaff is just getting passed around like a basic land. Replace that stuff with mono colored or guild cards and things immediately improve even if you suddenly have one extra Simic or Red card. OCD levels of balance in your cube is not doing anything useful besides making you feel good when you look at your cube in cubetutor. Resist the urge to do this.
"Long have legends spoken of The Bloodforged Battle Axe, it ushered in great war and fueled it spread; all have seen one but none the original as it is said to reside in the Lich King's Necropolis. They say his final wish in life was for war eternal, and by his blade it continues to this day."
Here's the thing though. There would be literally hundreds of thousands of these axes everywhere. One battle and you'd easily make 10,000 or more. A few centuries of war and you'd have land fills with these things. It's basically a Tribble Axe. Your entire campaign would have to revolve around how you stop the world from being overrun by bloodforge axes. Oops, cut myself sharpening the blade. Bam. Another axe. Actually, why even sharpen it? Just cut myself and get a new one.
Cryptbreaker really helps make clunky hands better. It also randomly helps when the game stalls since that is when the card draw tends to be active. If you have a sweet draw where each turn you are making a really optimal play, then cryptbreaker can look bad. Sure. But most games don't go that way. Even ones where you start off good and then 3 lands off the top of your library and you start falling behind on the board. Cryptbreaker puts those lands to use. It works in the opposite situations too. You have two land, a one and two drop. Three cards to find your third land. Doesn't happen. Well, toss stuff and start making zombies, draw an extra card when you get two tokens to try and catch up on lands (while still keeping up somewhat on board development).
Best analogy I can give... Cryptbreaker is like that decently attractive person that looks pretty plain next to a glamour magazine. But since life isn't what you see in glamour magazines, in actuality Cryptbreaker is actually well above average and very likely worth your time and appreciation.
It's forged by blood, and when you hit a player you're drawing blood. Since the blade looks mystical with the purple *****, I imagine the flavor is that once the axe gets planeswalker blood it just starts the ritual process on its own. Makes sense to me when you factor in the art. And, if we've accepted cat people and planeswalkers and magical jittes and etc etc then there's not really a problem making another leap here.
Suspension of disbelief is not a problem for me at all. That wasn't really my criticism. It's more that this card strikes me as something that started as purely a mechanic and then someone overlaid some clumsy flavor on top of it to try and explain it. It's a bit lazy is all.
If this had started in reverse (as flavor), I don't think it would have made it past initial discussion because it's a bit lame as a concept. An axe that draws blood and starts it's own ritual to make copies of itself then drops to the ground for someone to pick up. I'm pretty sure this would get rejected as stupid by my D&D group and we let quite a few ridiculous things slide into our campaigns.
Maybe cut Vampire Hexmage. I never cared for Hexmage (though I don't run walkers so you may value it higher). It's double black with mediocre stats. Flesh Carver/Ophiomancer are better token producers so unless you need 3 black three drops that do that, I think Mardu strike leader is very expendable. You also have a lot of creatures in black and culling a couple I don't think will hurt you. Liliana, Death's Majesty makes creature tokens, so you aren't even losing a full dude.
Last cuts I'd be eyeing Dance of the Dead simply for being an eyesore of a card. Then probably go for the throat. You've got a decent amount of creature removal and 3 187 creatures, not sure you need GFTT.
I'll second the desire for another Goblin Welder effect not stapled to a planeswalker. I'd also be a fan of more devotion type effects since I feel mono colored strategies need more love in cube.
So the best cycle you didn't list are the shock lands by a country mile IMO because of the basic land type interaction with fetches. I also think they are simply well designed since the drawback for entering the battlefield untapped is real and that creates a meaningful decision point during games. After that, it's a toss up for me between pains (just all around solid), temples (scry is a great mechanic on a land), and bicycles (cycling is great plus basic land types). Temples/Bicycles are even better if you also run bounce lands as the interaction between the then is synergistic.
After carver/ophio I think things are pretty interchangeable honestly. Run what you like. I'm still a fan of Hippie since if it doesn't get removed it wrecks havoc in ways other black 3's simply can't. Nighthawk is good value. Nothing wrong with that card at all. Geralf's Messenger is awesome in mono black, if that's a thing in your cube. I also still like bone shredder because it self bins making it easy to loop value off of. I prefer all those cards to strike leader. Drana I was not interested in testing since pure black aggro is not something I push in my cube. I'm sure it's very good there though.
My current cube is completely unrecognizable compared to the first version I built which was based on an outdated list from Tom LaPille. It was way too top heavy and basically a complete mess. This site in particular has been invaluable. As my lists are generally retro themed, I tend to rely on historical data more than current data for card choices and the archives here are quite useful for that.
Cube being a largely casual format (and generally singleton), it's a lot more resilient to the effects of what these types of cards tend to introduce into the meta.
And again it comes down to context. FOW adds some negative variance. Combo decks probably benefit the most from it's inclusion, though really any deck that has a really strong play that wins if it resolves will want FOW. Does your cube need that? Are you players down with swingy games of Magic? If yes, run FOW. You'll like it and probably consider it a staple in your meta.
Again, it's going to be completely meta dependent. There are counter spells I'm not running that I could run. Does it change blue's identity a little? Sure. Is blue worse off? Not really, it just has a slightly different role in my cube.
If you love memory lapse, by all means run it. It's certainly good enough for small lists. But it't not essential. Very few cards actually are despite people constantly labeling things "staples". You would have to try really really (and I mean REALLY) hard to get a selection of cards together that made cube a bad experience. Half the time people argue X > Y, the difference is often negligible. If you took all the loser cards form the X > Y posts in this thread and made a cube exclusively out of them, you'd have an amazing cube. And that's why I think it's a lot more useful to answer the "this or that" question with context. Why you'd want to run card X or where it would shine. Ask yourself the question "do I need this effect or more of this effect"? Because it's a lot more useful than asking "is this card good enough" (virtually every card that gets asked about in this thread is good enough).
Repeal as a cut seems like a good recommendation. It's solid but sometimes expensive for what it does. I really like Compulsive Research and would not cut that one personally. Gilded Drake I can see being cut but it's also pretty degenerate with any sort of bounce or blink effect. I like it. I don't care for Thing in the Ice so if you want to cut a creature, that's the one I'd be looking at. Condescend or Memory Lapse if you want to shave a counter for FOW. Condescend is perfectly fine but not better than other choices IMO. Memory Lapse is basically remand and you may only need one unless Ux tempo is super popular. Memory Lapse is very good but also not something I think is essential.
Cuts in blue are hard. The pool is very deep and a lot of card choices come down to what your meta needs specifically. So we can only guide you so much. Every card listed is very playable and can be the right choice depending on your playgroup.
My group was not a fan of unfun cards, so anything truly rage inducing generally got cut. The worst offender was Bribery. Land destruction and discard would be next on the list of things most don't care for. That said, outside a handful of cards I can't think of anything specific. Wildfire/Upheaval I suppose. I would not cut either under normal cube design parameters, but they also tend to get a high scoop percentage and I know at least one guy who hates playing against a deck with either (pretty sure he's hate drafted those cards).
As far as running 3 color cards in general... I've been all over the field with respect to that. My last cube project was designed around shards/wedges specifically and was intended to be modular in an effort to deal with variable draft sizes. The basic idea was five 90 card modules, each focused on a wedge/shard combination. One color overlapped and so you have a bias in each module towards one color (hence 5 modules total - one for each color). Worked well when you did 3 modules or more - had a lot of variety and was very interesting since different combinations made significant meta changes - slowed things down/sped them up/altered which strategies had advantages. To some extent though you were railroaded a bit into which color combinations were viable (or at least easier to do), but the list was so synergistic within modules and across them that it was almost impossible to wind up with something unplayable even if you took the hardest color combination and forced it.
In that modular cube, despite the focus on wedge/shards, I ran no true tri-colored cards (tribrids only). Mainly due to how narrow 3 color cards are during draft. Either draft exactly deck "X", or this card doesn't make the list. In some ways, these types of cards are worse than narrow combo enablers. I'm generally not a fan of supporting 3 color gold cards. That said, there are a handful that I think you can make exceptions for without hurting your drafts too much (power level aside). Sphinx of the Steel Wind works in any cheat strategy (including tinker) where the actual mana cost on the card is largely irrelevant. Something like Progentitus can pass if Natural Order into it is a thing (though most cubes run more powerful options now). Maybe one of the Bolas Walkers or Cruel Ultimatum (though the latter is again narrow). I've always loved Lightning Angel and in a lower powered list would splash for it if I were already in two of the colors (conventional power lists probably not though).
Regardless, I don't support the idea that cubes should be forcing one card per wedge/shard even if you opt for some of these fringes exception cards. The quality drops off too much and whatever balance you think you are maintaining is being undone during the draft when the chaff is just getting passed around like a basic land. Replace that stuff with mono colored or guild cards and things immediately improve even if you suddenly have one extra Simic or Red card. OCD levels of balance in your cube is not doing anything useful besides making you feel good when you look at your cube in cubetutor. Resist the urge to do this.
Here's the thing though. There would be literally hundreds of thousands of these axes everywhere. One battle and you'd easily make 10,000 or more. A few centuries of war and you'd have land fills with these things. It's basically a Tribble Axe. Your entire campaign would have to revolve around how you stop the world from being overrun by bloodforge axes. Oops, cut myself sharpening the blade. Bam. Another axe. Actually, why even sharpen it? Just cut myself and get a new one.
Best analogy I can give... Cryptbreaker is like that decently attractive person that looks pretty plain next to a glamour magazine. But since life isn't what you see in glamour magazines, in actuality Cryptbreaker is actually well above average and very likely worth your time and appreciation.
Suspension of disbelief is not a problem for me at all. That wasn't really my criticism. It's more that this card strikes me as something that started as purely a mechanic and then someone overlaid some clumsy flavor on top of it to try and explain it. It's a bit lazy is all.
If this had started in reverse (as flavor), I don't think it would have made it past initial discussion because it's a bit lame as a concept. An axe that draws blood and starts it's own ritual to make copies of itself then drops to the ground for someone to pick up. I'm pretty sure this would get rejected as stupid by my D&D group and we let quite a few ridiculous things slide into our campaigns.