Honestly, I don't know. I can see DS2 getting a NSMB follow up and Wii 2 getting a new 3D Mario instead, with a 2D one coming somewhere down the line.
On the other hand, I heard something about a new 3D Mario on DS but that's probably just someone's wishful thinking.
But what if they reversed it? 3D Mario for DS2 launch, 2D Mario for Wii 2 launch. Who'd see that coming?
Tag - "No trolling on my watch!"