What was it that got Kahn stranded on city alpha 5? Genetic manipulation and attempted takeover of kirk's ship, correct? If so the takeover of the enterprise by Kahn wouldn't seem to me to be big enough story for the next Star Trek. They would have to fill it out some.
I just don't see a Star Wars/Star Trek story line. Way too much hollywood political baggage connected to that idea.
If you don't have a seat at the table, you're probably on the menu