I'd really like a retro throwback, graphics-wise, cut the silly 2.5D stuff and go back to the beautiful sprite stuff from SMW and SMB3, it's a sidescroller, plus, running on Wii U, the artwork could be incredible. The maps from the overworld would be welcome too, SMB3 and SMW's maps were packed with secrets and as already said, often let you choose your difficulty through their secrets if you paid close enough attention. Mega Man did it, why not Mario? It'd be very easy to sell as a whole 'the legend returns to his roots' sort of thing, so it would be good fiscally too! Bring back the retro! :D







