http://www.polygon.com/2013/4/5/4189114/wii-u-miyamoto-miiverse-updates
Miyamoto likens hesitation about the Wii U and its touchscreen controller, the GamePad, to similar feelings about the Nintendo DS and its two screens.
“I almost feel like, as people get more familiar with Wii U and these touchscreen interfaces,” Miyamoto says, “that there is going to come a point where they feel like ‘I can’t do everything I want to do if I don’t have a second screen’.”
I’ll admit to being wrong about the DS before it came out, but the use case on the DS was obvious from the moment that you flipped it open and touched it with the stylus. The second screen would often provide user with feedback about the game, and I think that’s what they were hoping for here.
The problem is that the television panel is a strange beast, and having to look away from the main screen and back again isn’t the same as having a second screen that can provide feedback without having to refocus.
