Wow, just wow. Alan didn't come back because at the time Singer was in charge of X3, he didn't sign a contract. They did not get along, at all. And Alan hated the make-up process. There have been so many quotes from Alan about that.
I don't know if any one here knows the process of making a movie, but the actors are the last people to see the script and they are bound by it. Stop blaming them, and yes I'm talking about Berry.
It would be the same as blaming Famke for, "I dunno {shrug carelessly} or James for, "Storm, fry 'em," while being inside a giant copper statue.
First and foremost, a change in writing is essential for any resemblance of the characterization of the source material. People who know and understand that there is more to the X-men than just Jean, Rogue, and Wolverine. That Mags and Xavier are more than MLK Jr, and Malcolm X. Writers who know that Scott and Storm lead, and to not have them be efficient wise and successfl leaders is to take away from their character.
This is why I never want to waste my time on another X-film. NONE of them got it right. Too much was cut, not enough was put in, few people actually mattered, to many extras, too much forced emotion, not enough fun, way way to much blah...
They need a tv series. End of story.