I would love to see the NMBC overlay at the WDW Mansion, but apparently WDW gets more foreign visitors that aren't familiar with the movie. (although they do it at TDL...) I like the WDW's exterior better since it looks more imposing than the DL one, plus since it's a bit bigger it seems more realistic that the ride could exist inside the facade itself.
I really would rather have a new storyline than a copy of the DL one, since this mansion is completely different. I think they should dig up some older revamp concepts, some of which were shown in the HM:FtMKttM book. One of these is a face that stretches out from a door, like the effect in TDL's corridor of doors. Another one I liked was an elaborate revamp of the loading area.