I read your series today and I really liked them. Your opinions are well supported, and your analysis covers each keyword from many different aspects in a broad view.
I have one correction to make though. Suspend wasn't the first ability to use the exile zone in a way that no other card could, imprint in Mirrodin block did it first (albeit in an unexciting and not very memorable way). This mechanic still has quite a lot of untapped design space.
I don't have an idea what the first keyword would be. Trample is one of the most beloved mechanics of all time, that plays well and has history. However, it's not very innovative - many attacking/blocking mechanic have been made alongside it from the very beginning, and it's not as resonant as flying.
OTOH I definitely know what will make the worst ten keywords of all time: Shroud!
https://mtgcubecrafting.wordpress.com/2022/06/02/streets-of-new-capenna-and-kamigawa-neon-dynasty-update/
Selesnya is so bad, we actually only play three cards... What are your top three cards? I consider Knight and Finks the clear top two, so we might be missing a few gems. And yes, Finks isn't what it used to be.
https://mtgcubecrafting.wordpress.com/2022/01/15/2021-update-green-multicolored-colorless-and-lands/
https://mtgcubecrafting.wordpress.com/2021/12/30/2021-update-black-and-red/
Thanks! It means a lot!
Adventures in the Forgotten Realms
Innistrad: Midnight Hunt
Innistrad: Crimson Vow
See the update here:
https://mtgcubecrafting.wordpress.com/2021/12/23/2021-update-white-and-blue/
Oddity >= Poulkranos >> Master
Iteration > Sprite > Mind
Shade > Siphoner > Reaver > Jadar
Tracker > Prowler
We also play Kalitas, Taritor of Ghet and The Scarab God as cards that care about zombies. Warrior is relevant for Najeela, the Blade-Blossom, Mardu Woe-Reaper, and Kargan Intimidator. Its tribes are a small, but relevant advantage.
The card has a solid body for the cost, so aggro decks would play it. Graf can sacrifice a self-recurring creature for card advantage. It can also sacrifice itself just to be reanimated and kill another planeswalker later.
Ferocidon, it is more splashable and more aggressive.
Nightmare Shepherd heavily disappointed us, I'd comfortaby say it is the worst of the three. Braids is fun, but slow, fragile and inconsistent, so I'd test Dracolich over it. It might be worse in the long run though.
Shardless Agent. It is the narrower card of the two, as it doesn't work with counterspells, but it is a solid two for one in the right decks. Growth Spiral is not meaningfully better than the mono green options for me to cube it.
Maul >= Blade >> Sword. Not coming with a creature attached is a big drawback. Maul has a high initial impact, and while inefficient, does provide reach to the white deck. Blade is just some very convenient value that slots easily into decks. Reads bad but plays quite well.
Cut Feast and Famine
Looking forward to your update!
https://mtgcubecrafting.wordpress.com/2021/06/27/modern-horizons-2-update/
Sorry for the late reply, I didn't see your response. Black is widely accepted as the weakest color in this cube. Double Stroke feels broken to me, I constantly first pick it. It sometimes pops up often in decks that only have "fair" targets, such as a double removal spell. Players here think it is fun and want to keep it.
Power Play is best in aggro decks by far, although a high pick in general. I like it, as it adds consistency in a way that feels fair - you could always be lucky and be the starting player without it (yes, Power Play does more, but not a whole lot more). Advantageous Proclamation is a much lower pick; it allows you to shave two spells from your deck in one pick, but that's it. Decking is sometimes relevant, and some cards mill or care about how many cards you have in your library, such as Shelldock Isle. Figuring out land ratios is difficult with this conspiracy.