I'd be fine with Khan in a film and just as okay without Khan. So long as the end result is basically a good movie I'm happy.
With all due respect, that's a completely empty statement. I can say that the next Star Trek movie should be about the Borg going back in time and trying to assimilate the TOS crew, and that would be objectively a pretty bad and lazy idea.
Objectively?
Well no. It may be an idea we all agree is bad, but that's not quite the same thing as it or any entertainment concpet being
objectively bad. "Time travelling Borg is a lazy plot device" is not a statement on the level of "2 + 2 = 4."
I have very specific reasons why I think it's a terrible move for the franchise to have a plot surrounding Khan (the main one being that all it will do is keep the franchise stuck in time, living off old glories long-past),
If this is your problem, then the issue is with J.J. Abrams reboot in general rather than Khan in particular. The previous film had returned to the 23rd century, to Kirk, Spock, McCoy, riffed on quotes from
Wrath of Khan and the TV series and had Sulu mention his fencing and this and that and the other thing. I don't think it'd be that wrong to say the film reinvented and repurposed a lot of very familiar Star Trek content, and proceeding to use one of its most famous villains in exactly the same manner would be
consistent with the direction the franchise is currently in.