The fact that they all start with the castle in the BG is the dumbest thing to base the full game on. I'm not saying that it won't be a rehash, but when all you have to go on is a fairly iconic building in the BG, you are grasping at straws.
EDIT- You also have to consider that one of the first things they said about it is that they plan on rethinking the Mario platformer with it, so they obviously have something in mind that they aren't showing.
EDIT- You also have to consider that one of the first things they said about it is that they plan on rethinking the Mario platformer with it, so they obviously have something in mind that they aren't showing.