Is there a very noticeable difference in the look of the game?
I know the Wii isn't HD, but it can still pull off some pretty amazing visuals, considering it's last-gen tech and all. So I would imagine it can pull off the look of this game without having to turn down the graphics and detail. However I have seen some awful Wii ports, and am leery about getting it on Wii if the PS3/360 version is leaps and bounds better looking.
The reason I don't just get it on an HD system is because Wii is the only system I will let my 5 year old play, and this game looks like it would be a lot of fun for her.