Re: What was wrong with the current trilogy?
I actually like Phoenix and the Cure in one film. I think if done right they could have complemented eachother (repressed power vs. unrestrained, limitless power)
Phoenix provides the group with their physical threat but doesn't have much in the way of the social commentary side of mutation. The Cure asks plenty of stimulating questions but without an immediate character to fight. Together they have both, and emotional wallop in spades too. I can't think of a more interesting time to have the cure as an option than when a friend has become a danger to herself and others because of her mutation (ironically no-one in X3 seems to consider it).
I do script/plot alterations in my dgree course and I'm currently writing a revised treatment for X3. It's a hell of a juggling game but I think it could have been great.