I know the majority of people won't give a shit (or even be annoyed at the possibility of a new Mii Music) but I reckon this has some serious potential.
As anyone that really got into Wii Music will know, it was actually a fantastic piece of software. I spent over 100 immensely enjoyable hours with it, and have longed for a sequel ever since.
If they sort the issue of track variation, especially increasing the number of Nintendo tracks available, then it could be a real winner.
I'll just quote my wishlist from the Wii Music thread...
Dual Wii Remote drumming is a must as well.
One thing's for sure, this is definitely a title that could make great use of the GamePad and Miiverse.