Not sure why everyone is always saying the Wii U is underpowered. ZombiU looks good and plays smooth at 1080p. I tried the demo and it was reasonably fun and innovative, just not my type of game unfortunately.
I think the Wii U hardware is actually pretty solid and innovative. They're just totally missing the software and have been for far too long. Once that changes they'll probably be ok, even if they have to go it alone. Too bad they won't give up on the region locking though, that totally sucks.