One more thing Nintendo should do in addition to a new 2d Mario adventure is to return with the turn based multiplayer. A multiplayer similar to SMB3 would be really cool.
It'd be cool to at least have that as an option. I mean in general playing together in the New series style is far far more fun than just taking turns playing like in the originals, but it'd be nice to have that option to take turns playing the levels in parallel.
Actually it'd be reallllly cool in a completely new 2d series if they changed up the multiplayer so that the screen is split horizontally and you're playing against each other in real time, and stuff you do in the level effects the level of the other player in some way, could even sometimes be competing but sometimes be cooperation to get passed certain areas. Damn that's a great idea! Could still be 4 player by having teams so to speak 1v1, 2v1, 3v1, or 2v2.