You make me melt!
Plus the fact that it would be cool to see Storm in a leadership position on a team like that again, trying to help with the image of mutants and being in the forefront. It would have been a more inspiring choice, I think, for a former leader of the xmen than Havok.
Plus, where is all of this suspicion of Cap coming from? you dont think he really wants to do more to help mutants by creating an Avengers team that serves as good PR and a tight example of humans and mutants working together?