OK he sold me on the game.
Reminds me of a old-GAF poster named BowieZ who posted a big thread basically wanting what I think this is. At the time I was more into linear course-clear Mario, but seeing it put into actual practice by EPD's steady hands makes me realize the true potential this model of Mario could offer.
And even though this could be a tip of the hat to the next main 3D game, if Galaxy and Odyssey taught me anything, it's that you can never really predict what that Mario team is going to do.