I've been excited about this game for quite some time. I'm a big fan of Super Paper Mario for the Wii, and although this game does not feature the goodness of a 2D sprite in a 3D world, I anticipate it will impress in different ways. The game does feature backgrounds that, according to Wikipedia, "visually simulates 3D computer graphics", similar to New Super Mario Brothers for the Nintendo DS.
The game also features multiplayer modes similar to that found in the Nintendo DS. While I have played the DS version and found the multiplayer to be adequate at best, the up-to-4-player experience you get in the Wii version is at the very least amusing to watch, but it should provide for fun gameplay. Just check out the three Yoshi's in the below clip.
The following review did point out that, in the case of multiplayer, the game does compensate for players that are, well, bad at the game, even allowing the good players to continue playing and postpone saving the character until further along in the level (think Rock Band but maybe without that 10 second timeout). Anyhow, be sure to check out this Ars Technica game review for more.