OK, here is what happened, I think.
Nintendo finished the WiiU and went around and showed it to developers, and they loved it. Then they all, the developers, started thinking, wait, can it do games other than Chase Mii and such? So they called Nintendo back and Nintendo confirmed to people like Sega and UbiSoft that Wii U could handle the current games they were working on like Aliens and Assassin's Creed, and everyone was happy. So happy that UbiSoft change Killer Freaks from Outer Space into Zombie U.
Well that's not entirely true not everyone was happy cause some people suggested some tweaks like more RAM, Direct X11 support and two Gamepad support and Nintendo obliged. So Bob became everyone's uncle and Wii U's specs were finalized with a 4-5 year shelf life in mind.
So whatever the specs of the Wii U gpU are, the bottom line is that developers that Nintendo have in mind concerning games to be in development in the short term are happy with the Wii U, I think. 
Nintendo Network ID: DaRevren
I love My Wii U, and the potential it brings to gaming.
