No, Pike is not ignorable. Not only does he recommend and praise Kirk as an Admiral (which carries a lot of weight on it's own), he does so as Kirk's former commanding officer. That's saying a lot at a time when Starfleet is still small by comparison (even more so since it just lost so many ships).
So what? That does not mean he must play a role in the next movie. Starfleet Command itself may only appear by reference, if the action doesn't take place on or near Earth.
They could include Pike, sure. But they can just as easily not mention him again.