It's still up in the air but most likely will be using unified deck construction rules, so 1 sol ring total, which means almost surely it is correct to play a green deck and rock deck - and kinda discourages the typical flash hulk stuff because a strong flash hulk deck leaves the other deck as mono red or mono white with no rocks. Or a mono blue deck with all the counterspells used up.
My current thought is - to avoid fetchland overlap and rock overlap - Azusa strip mine tribal and Baral counterspell tribal. Azusa is much stronger with the degenerate rocks but can survive without them (or maybe just the ones that enable turn 1 Azusa, e.g. Crypt).
I had a lot of thoughts along the lines of Edric / Yuriko, Edric / Edgar Markov, etc., which I think may be slightly more consistent.
Some other random thoughts I had while noodling:
1) Cards like Silence and temporal mastery go waaaaay up in stock in 2hg. Similarly Fog effects are quite good if your opponents are not trying to combo, since there's only one combat step to worry about.
2) it's probably a mistake not to have a strip mine/loam/crucible deck (I think?) given how insanely strong those effects are in 1v1
3) Playing a metric %$#% ton of targeted interaction is almost surely correct - even stuff like Diabolic Edict is very very good.
4) Given the inevitability of people playing lots of mana dorks (because they are great and the only real option opposed to mana rocks for ramp), cards like Electrickery and Massacre are probably pretty good. But it really depends on how much people tune their decks.
5) Effects that trigger each turn (e.g. rashmi, seedborn muse, unwinding clock) are quite a bit less powerful. Even mystic remora is quite a bit worse with two opponents instead of 3 and the likelihood one of them will be creature heavy because of unified.
6) Fast commanders feel pretty important; by the odds the game should be MUCH faster, so being able to play your commander early feels like a pretty big advantage (yuriko, edric, azusa, etc.) -- eminence commanders are also potentially quite good (oloro, edgar and inalla seem best).
7) Stax effects feel much better; tanglewire is brutal, hitting both your opponents for 4. Orbs feel very good too although winter orb somewhat worse (since incentive is high to play nonland ramp as it's faster). other sac effects like Smallpox and Crack the earth seem particularly good.
--subnote: Commanders with stax effects that do not hurt your ally are doubly good, like GAIIV and Lavinia
8) Planeswalker commanders feel potentially very good since you only have to worry about two opponents and your ally can block for you.
9) Discard spells feel a lot better, especially with only one deck really getting to run counterspells; my thought is that not playing Black and Blue both in your cardpool is probably wrong?
10) Karador seems...really good? Basically 100% more free casts than you'd normally get, and the edicts and catterpillars forever are pretty strong. And he's in the color to be very complementary to an artifact ramp U deck.
11) Dragonlord Dromoka's effect is amplified quite a but, basically reads "My partner may combo off whenever" - so possibly the ideal partner to a UBx combo deck like Kess.
I'd love to hear your theory crafting thoughts.
--Note: my cardpool is basically everything except Workshop and Twister, which is a bit of a bummer because I think shops would be pretty good in this format; turn 1 Tanglewire is insane.
--NOTE2: I am not interested at all in discussion of problems with this potential format. I know them all and agree that it's dumb. But I like a deckbuilding challenge.
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