I think Nintendo will make the next Mario more "fan friendly", just like they did with Zelda.
For all its creative eccentricities, Nintendo still loves money, and if that means a somewhat more "fan pleasing" product, that's probably what will happen in the end.
So I think that will mean bringing back lots of level and environments and probably nicer graphics too and a lot of old-school nostalgia thrown in, with the innovation coming from the new controller (if it is for Revolution).