So, Mario Kart 8 moved consoles despite Wii U design

[Soundwave]

VanceIX said:
Zelda U will move even more units, as would a Metroid Prime 4. Zelda U is confirmed, Medtroid Prime 4 isn't. C'mon Nintendo, get to it!

Zelda U isn't moving more units than Mario Kart. 

Mario Kart > NSMB > Smash = 3D Mario > Zelda

When it comes to sales.