Um, some of the demos were actually PS3/360 versions, lol. Not as good? Maybe the Wii Spots type stuff which looked very much like old Wii games.
Just a side note: IBM Says Wii U Uses Watson's Brains (you know, the computer that beat people on Jeopardy)
http://www.1up.com/news/ibm-nintendo-wii-watson-brains
While IBM wouldn't reveal the processor's clock speeds, The Wii U uses a 45nm custom chip with, what IBM states, is "a lot" of embedded DRAM.
I also watched a video of the Wii U controller in action and it seemed better than I expected. At least, the comfort/weight issues people considered do not seem to be a problem.