Leonard Nimoy was in JJ Abrams' Star Trek not because he was appeasing old fans and passing the torch to a new Spock. Its because he's marketable!

Talking to SciFi Wire, Nimoy hinted that, depending on what the writers end up planning, we may see his Spock:

I have no illusions on whether or not they need me. They decided that they wanted to make this film using Spock as kind of an anchor for the story, which I think worked very, very well. They don't have to do that again. If they decide they have a role for me to play, I would be very interested in talking to them about it... My sense is that he has some work to do. He talked about establishing a new Vulcan colony, and I think he will be very involved in that. If we never see him again that is what I would imagine he is doing. He is busy rebuilding the Vulcan story.

Should he really be in the next movie? Should the Shat be in as well? 

What's next for Spock Prime? Trek's Nimoy speaks [SciFi Wire]