Hiroyuki Kobayashi of Capcom has said that:
Unfortunately, RE6 will not be available at this time on the Wii U. Right now we’re concentrating on the PlayStation 3 version, 360 version and the PC version of the game.
The three words that everyone is focusing on though is “at this time”. It makes it sound like the game may come to the platform later on, perhaps. When developers remain vague like that though, I tend to think it’s more out of habit rather than careful word choice. It’s rare they want to say anything that’s too concrete, as they can never be sure of how quickly things may change.
Or maybe I’m wrong and it’s just a matter of time. Hopefully that’s the case.