I'm sure if it has to have a centre asile that can easily be done by shinfing around the rows, has happened at some shows before, but I guess the producers would have to see if the want to go through all that fuss.
I;ve never saw cats on Broadway (and I regret not doing so) but from pics I;ve seen and things I;ve read, they basically removed chunks of the proscenium to make it wider and higher so it felt like there was no roof, and everything was painted black and covered with carbage so it was hard to tell where the side boxes were. And unline london they didnt have the revolving stage.
http://www.flickr.com/photos/27199361@N08/ Phantom at the Royal Empire Theatre