I don't think SMG2 was bad, it was just as good as the first. Only thing is that the first one was revolutionary while the second, well, was not. I've completed it two times as of now.
But for the next "true" 3D Mario, I don't necessarily want a Galaxy 3. All I want is a Mario game with 120 stars. And hopefully an overworld that is fun to explore.
EDIT: Hopefully the team will learn from the Zelda team that you don't need super linearity or handholding in every game.
Yep.







