Obviously the story would not be best served by his presence in the eyes of the filmmakers. I have neither a pressing desire nor vendetta regarding Kirk's appearance in the film. The reason I take this stance is that I have no idea what the story is going to be. Just like anybody else not working on the production. Having Shatner in there just because he's William Shatner would be a horrible idea if the story isn't intended to suit it.
I'll trust the folks making the film until I see it. If for some reason after seeing it there's an obvious reason Shatner would have made the film better, I'll call bull.