Greenwood isn't even certain if his character is returning for the sequel. The same production team is behind it and not much has been said about the proposed plot.
Will it be a big-screen version of one of the more popular episodes of the original series? Perhaps the return of Harry Mudd? Or Khan Noonian Singh? Given the animosity between Harlan Ellison and 'Star Trek,' it's unlikely to involve the Guardian of Forever.
Or they could do something original (is there an original 'Trek' plot left?). Or perhaps have Kirk fight the Borg since they're not under any sort of continuity obligation. What would you like to see in the 'Star Trek' sequel?