What I don't want:
Over-the-shoulder camera. - I won't care if it's a secondary option though
Player feeling like a tank - I want the movement to feel light similar to Banjo Kazooie, the person from Shadow of the Colossus, and some other. I do NOT want it to feel like a delayed player similar to some third-person games.
The hub world being only the cave - Having both would feel much better.
Repeating - I like each world to be remembered. I even like to have optional backtracking like one guy said. Though I don't mind myself if there was a small amount of forced backtracking as long if it's not like DK64 ways in a level or worse.
Generic worlds. - I mean at least make each world have something unique in general if we use stuff like 'Grass', 'Snow', etc. Though I would love to have other world backgrounds other than the [i]New Super Mario Bros series.[/i]