The concept is a dud. They told everyone that complicated controllers were dead, that the future was about motion control, and laughing and jumping and having fun...and then totally reversed course. Now the message is the same complicated dual analog controllers as the other guys with a tablet stuck in the middle. It's confusing, and convoluted, and not nearly as much fun.
The Wii U is Iwata grasping at straws, unsure what to do now that the casual market he was so proud of is happy with iPads and Smartphones, and the core is perfectly happy with Playstation's and Xbox's and PC's. They have no quarter. The Wii U is what happens when a company has a hit, squanders the good will and marketshare that hit built, and has no idea how to catch lightning a second time.