Just an observation on some of the comments I've read: I don't know where people keep coming up with this idea of superman Khan wanting to wipe out less perfect humans...the whole eliminate that which is imperfect is Nomad's bailiwick, after all. Khan just was super ambitious and thought his superiority meant his kind was meant to rule.
It's from the movie itself. Before NuSpock beams over Khan's crew, he asks Khan what he'll do with them. Khan says he'll continue his "work" and Spock says, that as he understands it, his work is the mass genocide of any beings he finds to be less than superior (which is, apparently, the information he got from Spock Prime).
nuKhan has been dumbed down as well. Khan's plans were a lot more complex than just committing mass genocide, he's not Hitler.
In the new timeline, apparently every villains seeks vengeance and wants to kill everyone else.