They'll surely nerf combo decks taking into account what they said: "we are going to allow turn-four combination decks, but not decks that consistently win the game on turn three" (IMO too aggresive rule because even some aggro decks break it). On the other hand nerfing combo will surely make the 12Post vs Control issue harder to resolve.

So, at first I was more in favor of just nerfing 12post (emrakul f.e.) but now I'm more about killing the deck. Emrakul is very hard for Control (I could even agree that it's too much inevitable) but I don't think that it's too much logical to be surprised about autolosing to a casted card of 15 mana (Other theme is Emrakul in combination with cards that break that cost barrier like Goryo's Vengeance). Then I think that the solution is more about killing the engine that it's not other than Cloudpost.

I mean that if not Emrakul other strong option against Control should be there. Such a big mana advantage should be enough to beat Control, otherwise I'd found it very rare. Maybe you can currently palliate the visible results of an unfair mana resource (banning Emrakul) and in future editions return to the same problem because you haven't atacked the root (Cloudpost).

But my problem is that I'm not entirely sure that 12post mana advantage is unfair enough or that Emrakul is fair enough even withouth 12post. What I can have clear is that the combination is veeeery hard . For example maybe now it's all ok with Cloudpost out and in a year we miss it because it was a nice way to regulate a heavy control metagame.

I just hope that wotc knows the right move.