I doubt the current building is as large as Shanghai's. Perhaps if they were to combine it with Philharmagic's building, but even then I don't know. Seems like it's larger than WDW's. Also I believe it uses a somewhat different type of ride system. I thought I heard it said somewhere that the ride system was based on the Monsters Inc Door Coaster concept, and it does seem to have certain coaster-like traits.
IF WDW ever receives an update, it's more likely to follow the alterations that were made to Tokyo's version of the ride within the past few months. It just received a MAJOR overhaul, but prior to this it was a 100% identical clone of WDW's. Here's a video of the ride post-refurb (keep in mind that before this it was identical to WDW's)-
The overhaul brought it somewhat closer to the Disneyland version, though kept a fair bit of the original scenes. The nursery and London scenes are mostly the same, just with some minor tweaking and new lighting/projections. The same is also true of the scenes from Hook's ship onward, mostly the same but with new lighting effects and other minor but nice upgrades. The soundtrack was also retained, instead of the Disneyland variant. The biggest changes are the middle third of the ride, the flight over Neverland. They have basically gutted and rebuilt these scenes to be very similar to DL's, including the miniature model of the island (surrounded by the star field) and the more effects-rich and detailed Indians, Mermaids etc. Quite a difference.
So if WDW's is ever overhauled, I think it's most realistic to expect Tokyo's to serve as the template. I do think Japan's refurb is a mixed bag. The effects they added are definitely a huge improvement, and individually I like the newly redesigned Neverland scenes (though the miniature model of Neverland is kind of poorly designed/shaped). I do think the pacing was negatively impacted a bit due to the space constraints, and some of the forced perspective effects to simulate altitude changes are a bit worse now. I also wish they had imported Disneyland's soundtrack as well. The upgrades to the original scenes though are generally a big improvement, love the new lighting and such.