I think it's worth mentioning here that Wii U is the best place to play one of the best platformers ever made - Rayman Legends. Put that together with MK8, and that would be enough to justify the purchase of a Wii U for me.
But, yeah, the Gamepad seemed pretty stupid right from the start. I can only think that it seemed cool early in the development cycle, and they were too committed to it to scrap it before launch. Knowing what games were in development, Ninty could certainly see it wasn't going to be well used. And, even some half ass corporate spying would have told them that tablets were about to become widespread, and they were much cooler than the giant Gamepad (the thing reminds me of Game Gear, really). There really is no reason to have launched that thing other than just being too far in the dev cycle to turn back.