Well, let us break this down a little further. While you are correct that the Wii U games may tend to be more AAA in quality you have to remember this is a home console, it is not meant to be picked up and dragged around on a bus or train and the like.
You mention that if you were poised to pick one, such as Black Ops for the Wii U or the Vita you would go Wii U. Once again, this is an acceptable response when money is an issue because the console releases are console games and thus carry a bigger weight to them so to speak but the whole concept of the Vita is that portability.
For me, if I'm looking at Black Ops for the Wii U and Black Ops for the Vita I'm not comparing them and saying, "Boy, this Wii U title sure has the better graphics why would I bother with this Vita version?" I'm looking at them to see what I want out of them. Do I want a game for my couch? Or, a game on the go?
You see the Wii U and the Vita are completely different markets, someone is not going to go for the Wii U over the Vita but they may go for the Wii U over the 360, or PS3 since they are in the same realm.