First off, I don't own a Wii U so you may discredit the following as unenlightened if you so choose.
With that out of the way........
I feel like the gamepad would be a amazing if it was basically a stand alone device. Basically a gaming tablet, without the need for the console somewhere about powering the games. Because the gamepad actually is very very light and comfortable so I feel like it would make an absolutely outstanding core mobile gaming platform. I'd much sooner but that than a Vita or Nvidea Shield or whatever they're called. As a controller for games meant to be played on the TV though......meh
But that's just my 2 cents







