They should part the 2 from each other and just add a Wii Remote or Pro Controller in its place and sell the Gamepad by itself intill the tech for the controller has gone down in price.
So the Wii U could be what it is now but without the Gamepad and sell for $200 basic model or $250 Deluxe,then sell the Gamepad for $100 separate.So if this happened it would be the same boat as the Wii was by being alot cheaper then its competition which alone would steal a good chunk of the market away for them.