Agreed that firing Claremont to give Lee more control was a huge mistake that in retrospect is hilariously short sighted, but I disagree that Claremont wouldn't do something like this to a character. His willingness to make radical changes was part of what made his run great.

He had Cyclops leave the team to leave superheroing for good (not Claremont's fault that Marvel greenlit X-Factor), depowered Storm and kept her on as a leader, made Magneto headmaster, had almost the entire lineup change and go off to Australia, etc. Fatal Attractions was bad because the culmination of the 90s edginess that replaced Claremont's thoughtful characterization, but Claremont definitely had this kind of dramatic change in him.