Both Khan and Mitchell...hmmm.
How about this (not a spoiler, but speculation):
Kirk finds/discovers/runs into Khan and his peeps on the same mission that will result in GM's "issues."
Khan actually assists Kirk in addressing GM, but in to doing, Kirk realizes that Khan (and his followers) are not going to play nicely with others on Earth (and vice versa [remember, the new timeline still has all of the prior events up to the new timeline]) and utilizes the same "solution" as in the original series/timeline.
Just a thought.
I have a feeling that something like this will be the plot. Kahn hasn't had a chance to be marooned by Kirk yet so Kahn shouldn't have such hatred for Kirk yet.
Kahn's superior intellect and strength maybe what Kirk needs to defeat Mitchell.
This movie will likely set up the third movie to be a Kirk vs Kahn extravaganza. I just don't see how Bad Robot can remake the Kirk/Kahn chess match and out-do it or even do it justice.
The Wrath of Kahn is quite possibly the one story line that should never be touched.
But did anybody notice that point in the Japanese trailer where Kirk puts his hand on glass to match a mysterious hand?....kind of like what he did in The Wrath of Kahn when Spock was dying?
Needless to say, I'm super pumped about this movie.