Wouldn't you want to see Nintendo go the third party route? Nintendo is very good at utilizing unique hardware with their games. I would like to see what they can do with the Kinect and all the control inputs of the Vita.
It would be nice if all game companies made games for only one platform. Unfortunately, there's this thing called money... and you know, multiple competing consoles is a good thing as far as keeping prices low, and products good.
Mario vs. Donkey Kong is a hideously underrated game.