I think Benzema will never like rotation (just find the news about him talking about how his Lyon coach's rotation affected his performance). Most likely he will not join Man Utd. Forget about him.
Only those who never really care about if there is rotation or not would likely join Man Utd. This is perhaps one of the problems of rotation: you can't attract those who want regular football now. But... perhaps someday most clubs will begin to imitate Man Utd to have a "big size" squad, only then rotation will become a norm and every player just have to adapt to that then.