Wii U details keep squeezing out, the latest being that the hardware will be 3D capable for those willing to don glasses while playing with the LCD touchscreen controllers. Oddly, those controllers won't be in 3D, making for surely awkward transitions from touch screen to TV mid-game.
The news isn't terribly surprising, the Wii U hardware on almost an even playing field with the Xbox 360 and PlayStation 3 in terms of power, both of those current generation consoles spitting out dual images. It still comes down to the developer though, Sony ever vigilant in keeping 3D out there in the spotlight, Microsoft more or less a "meh" in the department, letting developers do their thing.
Nintendo seems to be taking the Microsoft route, CEO Satoru Iwata stating to the Mercury News, "If you are going to connect Wii U with a home TV capable of displaying 3-D images, technologically, yes, it is going to be possible, but that's not the area we are focusing on."
That doesn't rule out the possibility for a 3D Mario, just renders it unlikely. Besides, if 3Ds don't fit into Nintendo's plans, there's always a chance some of those handheld titles make the transition to the Wii U. Sony certainly grew fond of it, porting former handheld PSP exclusives to the PlayStation 2 and PlayStation 3.