A 3D Mario game that actually has brand new, completely different models for the Bros.? What madness is this? Seriously, though, I'm really interested to see how the switch to 3D will affect the feel of the game. In particular, I hope there'll be more open areas than the ones in the trailer in the final product; nothing in the series has matched Superstar Saga's Beanbean Outskirts in both breadth and depth, in my opinion, not even the overworld in BIS. Interesting that this seems to be such a direct, same-world sequel to BIS, as well; PiT and BIS may have had nods to their predecessors, but no recurring characters that actually played into the plots.
Also, what the Chef said.