TMNT bombed super hard. While by all accounts it's a great fighter, there's just no reason to buy it if you own SSBBrawl which is superior in all respects. I was looking at it at $15 and still couldn't justify a buy.
No idea what they expected from Academy but that also went to $20 extremely fast.
Rabbids Go Home is a flop in NA but sells well in Others which I just don't understand. I understand people wanting Rabbids to remain mini-games, and saw numerous people complain (amazon) that it was too repetitive and boring but still it deserves better sales.
Just Dance being the stand out success is just sad. It certainly won't encourage anyone to make quality games for Wii.