New variations to gameplay include objects that can be wielded for big damage - though it's weird to see Thor swinging a lead pipe with his trusty hammer Mjolnir is close at hand. Grappling is a big part of combat, and new charge moves enable big attacks if you have time to ready them. A large number of the characters have the ability to fly, and can do so without penalty. Spider-Man may not have flight, but he too can take to the sky with continuous web-slinging.
Obviously, control is quite different on the Wii. Attacks consist of shaking the remote in either up/down or side-to-side fashion. At the moment, it's not the most intuitive mechanic, and the delay between your actions and the heroes' offense is frustrating. It just doesn't feel like you're beating up baddies, and the onscreen characters are just not going to be able to attack as quick as you move (spaz). The benefit on this platform, however, is instant access to each hero's super moves by hitting the Z button and waving in a direction.
Marvel Ultimate Alliance on PS3 and Xbox 360 looks equally beautiful, and easily reach new levels of graphical excellence, just as expensive next-gen consoles should. The Wii is no slacker, but looks decidedly current-gen - missing the great lighting and detail of the others.