My response to that would be "That's preposterous! There's so much ridiculous new stuff in here already, and they don't need to go the extra mile to get everyone to buy it," but I would've said that yesterday about some of the stuff that got revealed this time around.Also: I think we are getting a Mario 2 setting with this game as well, it just hasn't been revealed yet.
I mean, when they are showing off the 3D land stuff, they they first bring it up, there is a blank space on the menu to the right of it. With enough room for another game mode.
And they demonstrate that the 3D world is so different from the main game mode it has to be its own thing. Just like mario 2.