Thanks for reminding me, Wario's Woods and Mario & Wario need to come back. I know Wario's Woods came back (for NES? Sheesh. I grew up with the SNES version). But they're pretending like Mario & Wario didn't exist, when it was actually pretty playable in its Japanese form. If I recall correctly, Mario & Wario used the SNES mouse. Well that should be easy enough to implement on the Virtual Console, just have the Wiimote's IR pointer thingy substitute for the mouse.
If they can do that, there should be nothing preventing them from throwing Mario Paint onto the Virtual Console either. Or any of the Super Scope games (which again was a point and fire affair), like the built-in pak or Yoshi's Safari.
There was Metroid and Super Metroid and Metroid Prime and Metroid Fusion... I guess the next Mario could be Mario Prime. But I can't think of any "pure" Mario thing since the New Super Mario Bros. and Super Mario Galaxy already did that. Well, what could Mario Fusion be like... I know, fuse Mario and Luigi together. ...which doesn't seem to help. Fuse Mario and Bowser, perhaps? Superstar Saga with rivals working together?
I don't know. I can't think of what a new Mario game would be unless it's totally off the wall. I know, have a game where Mario bounces off walls... aw, I think they did that with Mario Pinball Land.
