First watch this interview from the Darksiders II developers
http://www.youtube.com/watch?v=Tl3HGOsAlx0
Highlights
Developing for the Wii U "easier than the PS3, on par with the Xbox 360" (X1 and PS4 were not announced when this interview took place FYI)
Porting a game and adding gamepad features "took 3 programmers about 5 weeks." One of whom came during the middle of the development cycle. This was also with an early development kit.
Nintendo is "great to work with".
Gamepad "easiest thing to put stuff on" -- putting the main screen on the gamepad "took about 10 minutes".
EDIT: given that this is old, and THQ is out of business, I updated the title. Anyone know where these individuals work now? What are they developing for now? It'd be interesting to hear more about how'd they'd reflect on the experience now.
How does this (at all) change your perspective of the Wii U?
I predict NX launches in 2017 - not 2016