It makes me chuckle everytime something new is opening and people go "move phantom" as if moving a show on Broadway is that easy or cheap. it is terribly expensive to move a show. it costs almost as much as creating said show from scratch as there are endless union restrictions. It is much cheaper to do this in London thats why more shows in London seem to move around when needed. So phantom wont ever move, even though I think it would be nice in a smaller house.
I do love the Belasco, shame that it's location seems to be a disservice. it has one of the deepest substage areas which makes it great for set designers.
As for the shubert, i've only been in once for spamalot, from the outside it does not seem that big, is the stage and wing space considered on the 'large' side of things on Broadway?
MR's design lends itself to a theatre with a double box setting, but that can easily be altered.
Shame the old Hellger (spelling) is not available.
Also with the talk of winder garden, is school of rock doing poorly? if any show could transfer between that and Phantom it probably would be more likely to transfer that one.
http://www.flickr.com/photos/27199361@N08/ Phantom at the Royal Empire Theatre