Yeah, Trine looks awesome. I read a few interviews with the team and the designers seem to be focusing on the idea of "weight."
Facing off against the same puzzles/levels but solving them in class-specific ways is a successful recipe. I loved it in Donkey Kong Country (big strong kong, or nimble agile diddy) and also in Deus Ex (upgrade your STR, DEX, etc.)
The gesture recognition of the wizard, to create rigid bodies is also pretty cool. Black and White did that with spells, and also crayon physics did something similar.
Playstation Network and PC are listed on the site as shipping platforms, but I think this would be a cool experience on the Wii for sure!