Nintendo's focus on controllers began a lot earlier than the Wii:
With the NES they revolutionized the industry with the d-pad.
With the SNES they introduced shoulder buttons and the diamond face button interface to become the gold standard of controllers..
With the N64 they added the analog stick.
With the GameCube they fucked up.
With the Wii they skyrocketed with motion controllers with add-on capabilities.
With Wii U they fucked up again.
The problem with the GameCube was the shoulder buttons were wank, and they got rid of the diamond face configuration for some weird monstrosity.
The problem with the Wii U controller was that they tried to make it like a DS with your TV as the top screen, but it is awkward trying to look at one screen in your lap, while also looking at the othe in front of you. Plus the other feature of playing your games offscreen was not very functional due to it only having less than a 10 meter range, which meant it would probably be disconnecting if you were just one room away. Plus the controller was the opposite of the Wii - the Wiimote was slim and sexy, the Wii U contraption was fat and ugly.