MTG Salvation

I'll take a closer look at this when I get some free time, but I am popping in to say that according to official EDH Rules Council ruling, Extort has no effect on color identity, as the colored mana symbols only exist in the reminder text (this is also why Trinisphere is not black). So Crypt Ghast is just B, Blind Obedience is just W, and Treasury Thrull is BW.

Also just looking at generals, I see a glaring lack of Maelstrom Wanderer, who is hands-down the best choice for URG. I'd also consider Ruhan of the Fomorii over Zedruu the Greathearted. Your other general choices are largely similar to mine.

Alright, let's delve in here.

Generals:
I dislike Ulasht, the Hate Seed, and was only running him until something better came along. I believe that Borborygmos Enraged is that something better. Maybe you've had better experience with Ulasht than I have, but no one seemed to like him very much.
I find Momir Vig, Simic Visionary to be clunky and awkward. Edric, Spymaster of Trest isn't amazing without 1cmc creature support, but he does fare better than Vig does, at least in my opinion (and Theogony IX will back me up here if he shows up)
Rith, the Awakener is another very clunky dude. I love Hazezon Tamar infinitely more in this slot; He was also like my third EDH general ever built, but even discounting that influence on me he's a lot better for token decks.

White:
Serra Ascendant is notably absent. Is this because you don't like his effect in EDH? I realize he is very over the curve, but white needs a lot of help IMO.
In a smaller cube like this, i would likely stray away from Emeria, the Sky Ruin, as monocolored decks are going to be that much harder to construct.
Your top end of white seems to be missing a few things, notably Avacyn, Angel of Hope, Iona, Shield of Emeria, and maybe Storm Herd.

Blue:
Archaeomancer is better than Mnemonic Wall IMO, being cheaper and capable of carrying equipment, plus having more relevant types.
I see a distinct lack of clones here. You've got Phantasmal Image and Rite of Replication, but no Sakashima, the Impostor, Sakashima's Student, Phyrexian Metamorph, Vesuvan Shapeshifter, etc. I'd consider adding 1-2 of these, as clones are one of blue's major strengths.
I also think you have a few too many planeswalkers in this color (and you're not even running one of the best, Tezzeret the Seeker). I don't think all three Jaces are necessary. Jace 1 is probably the best here, JtMS and JAoT are generally a one-shot draw effect followed by a swift death.

Black:
I like your black section quite a bit. I might cut down on the Pox cards a little bit, as those can be pretty oppressive. Also, LotDR is probably the third or fourth black PW I'd consider, after Sorin Markov, Liliana 1, and maybe Liliana 2.

Red:
Gamble and Imperial Recruiter would help a lot with red's lack of tutors. I'd also add Wheel of Fortune and Wheel of Fate, draw sevens are insane in red. Chandra 1 and 3 are questionable at best and can easily come out.
I'd consider if you really want to be running this much LD. Especially when it comes to full wipes like Jokulhaups, they do a really good job of making games miserable and long. Consider instead running some damage-based sweepers like Starstorm, Earthquake, Rolling Earthquake, Pyrohemia, etc.

Green:
I feel like your ramp is lacking a bit here. I like the two-mana ramp spells like Nature's Lore, Farseek, Rampant Growth, Explore, etc. You're also only running one of the four search-two effects (Skyshroud Claim, Hunting Wilds, and Ranger's Path are the other three).
All Suns' Dawn seems pretty weak when it's only going to be getting back 2 or 3 cards. Try Restock instead?
Garruk Relentless unfortunately is GB by the Rules Committee's rulings.
You might consider a few more tutors like Green Sun's Zenith, Chord of Calling, Natural Order, Tooth and Nail, etc.

Guild:
I assume it's budget keeping you on Guildgates, Karoos, and Painlands over Shocks, Fetches, and ABU Duals? You might consider cutting one of your lands per pair, as you're running as many as I am at 600 + generals (on the other hand you have almost no 5c fixing, so maybe not). Your card choices here are alright, though I'm not sure what I think about Rosheen Meanderer and Sygg, River Cutthroat.

Artifact:
Painter's Servant seems questionable with no Iona in the cube, especially as you aren't running Oona, Queen of the Fae either. He's really only going to do anything with Teysa, Savra, and maybe Momir.
Oh, here's Phyrexian Metamorph. Again, by color identity rules, this is a Blue card.
Stax and Tax artifacts might lead again to some boring and unfun play, especially as they seem to come at the expense of mana rocks, which slows decks down even more.
Personally, I'd run a few more rocks at the 2 and 3 cmc slots instead, things like Felwar Stone, Mind Stone, Darksteel Ingot. Mana Crypt is insane if you can find one.
I like the better Swords (Sword of Feast and Famine, Sword of Fire and Ice, Sword of Light and Shadow) over the Kaldra set, but obviously the pricetag might be an issue there.
Your Utility Lands section is definitely small, especially given it contains exactly 0 mana fixing lands like Command Tower or City of Brass.

Just some pointers. Happy cubing!