I think this program as a LOT of potential, if Nintendo actually acts on it.
Wouldn't it be great if this turned into a program that allowed young students to practice their conducting skills? Young conductors tend to waver in tempo and generally when you're in a college conducting class and playing when you're not up on the podium, you're probably keeping a good beat. The student may have no idea how badly they're wavering in tempo, even after watching themselves in a video.
I'd love to see Nintendo pair up with MENC or something like that to release exercises for serious musicians, maybe downloaded via their WiiConnect24 or something like that. I just hope it's not some cheesy demo that gets tagged on with Wii Sports. If they really want to expand the gaming market, they have to offer things that would draw the non-gaming market in. I think something like this would be a great tool for musicians to use.