Well if they wanna stay somewhat true to the comic-story, I guess White Queen might be an option. Question is if they really wanna throw in yet another telepath.
Thing is the rumors say that they're heading straight for the Dark Phoenix saga, and skipping the good vrs, which I understand, because it's just a more interesting story to put on the big screen.
Ian McKellen says he really wants to do a third one, so I'm curious to see how that'll work out.