If it was going to outsell/match the GameCube, both Mario 3D World and Mario Kart 8 should've provided much larger boosts. The 3DS started to sell at a reasonably high level after Mario 3D Land and MK7, the Wii U is no where near as close to those levels.
It's still selling under the GameCube even for the equivalent months of June/July (2003 vs 2014), even though the GameCube had no notable releases during this time. That means the gap between the GameCube and Wii U has *grown* larger even despite MK8 and 3D World.
Doubling the baseline when your baseline was crap to begin with isn't really impressive.
Nintendo doesn't have many big franchises left. They have Smash Brothers, which also is going to have to compete with the 3DS version and basically they've spent their bigger gun IP.
A more cartoonish style Zelda is not going to move hardware.







