I like that Moira MacTaggart, Emma Frost, Mystique, Sebastion Shaw (6 Degrees of Kevin Bacon just got some new wrinkles), Azazel and Banshee are in it because they are all parents/mentors/instructors of current generation young mutants within the comics. So their inclusion makes sense in a prequel sort of film due to their age. Beast also makes sense within the film continuity because he was sort of an elder statesman type in the third X-Men film. Havok and Darwin don't make as much sense, though Havok's inclusion depends on the relative age difference of Havok and Xavier in the film. Still, as a long time fan of Alex Summers, I appreciate him being used in the movie.