Lol... The Gamepad is not the cost maker here. If you leave it out the Wii U bundle would be like 200.
I bought the Wii U from day 1 and I love the Gamepad. Why? The functions it has are just awesome. Really nintendo like awesome. And sure, it is a little big. Or bulky. And yeah, the screen loses color in front of your HD super screen. But ey, it's a controller! And it's possible to play games off screen. They even patched the Wii mode so you can use it as a second screen. How cool is that?
No if Nintendo would drop the support on the Gamepad then the whole purpose of the Wii U would be gone. What would be an idea was to make the Wii U gamepad optional. This way people can choose wether they want to play with that or with the Pro controller.
For Mario Kart I really love the screen! My setup then is awesome: Big HD television for racing, the gamepad with the support so it stands up with the map on it and in my hand I use the Wii remote in the Nintendo wheel.