I think the problem is that Phantom is DEPENDENT on its production to succeed. The Hal Prince staging and Maria Bjornson design are just as important to the show as the script and the score. Replacing those elements with weaker ones just brings to light the flaws in the material (and oh my there are flaws).
Oh, and I forgot to mention above - in Notes II, Christine slaps Raoul across the face. I couldn't. Even.