Yeah, Spock and Khan have an interesting history. I'm still pretty skeptical about another Khan movie, but if they're going to do it, I really think that Prime Spock should be a part of it.
I can see it:
nuKirk: Old Spock, how do I defeat Khan.
Old Spock: There's this completely dumbass chick with huge tata's. Her name is Marla McGivers. She goes for the muscle type. Dangle her in front of him. He'll go for that, you know, all tits, no brain, adoring type. Have her lure him to the transporter with the promise of a castle on the beach and a population to rule over. His minions will like that, they love to beat up women. Beam them all into outer space, and we won't ever have to be bothered by Carol Marcus and that little twit son of yours that causes future problems for me. Whatever you do, don't fight him hand to hand, he beats the shit out of you. Stick a bat in your pants and tell him you're happy to see him.
nuKirk: Sounds like a plan.