I couln't come up with a better topic name, but anyways, here's what the Activision person in charge of answering questions in the official forums said:
"Everything you'll be seeing is brand new. We're building Marvel: Ultimate Alliance 2 with a much higher level of detail than Marvel: Ultimate Alliance 1, and that means that visually, everything has to be rebuilt. Old textures just wouldn't look right next to the new textures, and old character animations won't work with our new models (as they have different proportions and different numbers of joints). So even stuff that's similar to the first game (like, "Spider-Man swinging on a web") has been completely re-done. Even stuff you wouldn't normally consider has been dramatically overhauled - like our renderer, which has had an amazing volume of work put into it to allow our massive damage and dynamic lighting to function without knocking down the framerates. There's actually a dev diary going up about that in a few months, written by our lead graphics programmer. He's a really brilliant guy, and it'll be a fascinating read for anyone who's interested in how next-gen visuals are put together.
There is some game code ("under the hood" stuff, congrats to FroBoy11 for guessing that ) that remains from Marvel: Ultimate Alliance 1, but it's probably less than you think, as nearly every system in the game has gone through major updates, revisions, and outright changes."
This does not bode well for the use of new models in MUA1.
I don't think we've seen anything from the PS2 version yet.
I personally think all the brand new stuff will be only for the current generation consoles whilst they'll use the old stuff in the PS2. I really doubt the PS2 can handle all the stuff going on in the previews we've seen.
Unless it's Vicarious Visions themselves saying that it's total BS. The reality is that the guys at Activision don't touch the code - it's Vicarious Visions that's building the engine. It's always been their engine since they bought out Intrinsic. Like Dihan said, our best bet is the PS2 version, since I doubt they'll put in as many changes there.
The bonus will be if the PS2 version runs on an emulator. Then no matter how many bones we're talking we can rip the files.
The guy actually works for VV. Sorry for the confusion.