Ever since the release of 2009's Star Trek, fans have speculated that the sequel will feature genetically engineered supervillain Khan. Personally, I hope these speculations come to nothing, because we've seen Khan's story before, done to perfection; why retread old ground? Besides, future-Spock's presence in the new alternate timeline should mean that there's no excuse for the Enterprise to stumble upon the Botany Bay as it did before and unknowingly awaken Khan. Surely future-Spock has given alternate-Kirk a "dos and dont's" list:
1. Don't take Gary Mitchell and Elizabeth Dehner to the edge of the galaxy
2. There's a planet-killer at these coordinates. Destroy it by putting an unmanned starship on autopilot and set it to self-destruct in the machine's maw.
3. Don't beat yourself up over hesitating for a second before shooting at the cloud monster.
...etc. But surely the top of the list would feature one overriding command: when you run into the USS Botany Bay, don't awaken its passengers! Leave it alone.
Of course, that wouldn't make a very exciting story. So if the producers of the new film insist on using Khan, the best way to create drama would be to have future-Spock attempt to guide the young Enterprise crew to a better course of action. He might, for example, advise young Kirk to tow the Botany Bay to the nearest Starbase and, under heavy guard, put Khan and his followers on trial for their crimes against humanity. That would be the logical and ethical thing to do.
But what if, in attempting to avoid the mistakes of the past, Spock's interference leads to even greater catastrophe? Perhaps Kirk thinks that only a trial on Earth will suffice for one of humanity's greatest monsters. Perhaps, complacent in their knowledge of the (alternate) future, Kirk and company forget the first film's most important lesson: that everything has changed. Perhaps Khan and company escape custody and execute some kind of horrific terrorist plot - perhaps one that kills Kirk's mother and brother? The film could be called "The Wrath of Kirk," as Kirk seeks vengeance and future-Spock realizes, too late, that attempting to change the past has only made things worse. He might even tear up his "dos and dont's" list, swearing not to say another word about his knowledge of the future.
I suppose this might make an entertaining movie, especially if it inverts expectations about what a Khan-based film should be. But truly, I'd rather see a film that harkens back to the show's original concept: seeking out strange new worlds and new civilizations. It would be unfortunate if the new creative team started rehashing old material one sequel into the reboot...