Calling it now: it's Art of Balance Neo.
And I'm happy with that; Art of Balance on Wii was a fantastic little puzzle game with a nice calming atmosphere and gameplay that was accessible, yet ramped up to be very satisfyingly challenging.
They also said in a previous interview that their Wii U games, plural, would use 4k-8k textures from now, so whatever their new game is, it will look gorgeous, and run at a delicious v-synced 60fps.