The only big mistake I see with Wii Music was that HORRIBLE presentation at E3, so bad it made people to hate that game and don't even give it a chance to try it out despite some good reviews and comments.
Had the presentation been made by JC from NOA, the game wouldn't be as hated as it is right now.
Castlevania Judgment FC: 1161 - 3389 - 1512
3DS Friend Code: 3480-2746-6289
Wii Friend Code: 4268-9719-1932-3069