Honestly I just don't "get" the direction of this film. Maybe it'll be more clear after I see the trailer. Is it grittier? More action? More character driven? More humorous? More romance? More serious? More retro-60s-ish?
How much are they going to change to make it appeal to the "mass" audience? I just have a lot of questions. Bringing back Nimoy at least gives them a bit of a safety net, and rebooting back the original iconic character types probably cuts through some of the "this is Star Trek part 15, right?" confusion.
If they're going to add Nimoy, IMO, unless the script really doesn't permit it, they go ahead and bring back Shatner. It's obvious he wants to be in it. Everyone purged Generations from their memory anyway
Though I suppose if they're talking about TNG-era Spock then Kirk and the rest of the original Enterprise crew would be dead along that timeline anyway.