Bruce Greenwood (Admiral Pike) commented to IFC about the motivation to keep as much of Star Trek sequel secret as possible. He also commented to Collider on his Pike role in the sequel by simply saying "wait to be revealed" on how much his Pike character will be in the film (if at all).
"So the audience can have an experience that isn’t complicated by having to pretend they don’t know what happens. It makes it trickier to conceal things so that when you see it for the first time you don’t know what’s coming, but that’s okay. You can’t blame people for being interested and excited, trying to find out. But everyone who’s involved in the film is committed to keeping it under wraps."(via TrekMovie)