Now don't quote me on anything because this is just speculation. Capcom and Nintendo have been best buddies lately with Monster Hunter being a huge success on both the Wii and 3DS; also when they release a Resident Evil game on a Nintendo platform it usually has very good sales with Resident Evil 4 Wii Edition selling over 2 million copies.
If you watch the full RE6 trailer, at the end the release date says November 2012. This would put the release right on or after the launch of the Wii U and perfect sense for Capcom to make it's first entry on the next Nintendo home console. It would most definitely be a port of the 360/PS3 versions but the Wii U controller could make for an experience that is even better with the usually cumbersome inventory system of past Resident Evil games made easy and more intuitive.
It seems like a no brainer for Capcom to release this on the Wii U. Resident Evil 5 didn't happen on the Wii so I think we'd all agree that Capcom owes Nintendo fans a true Resident Evil game and not another rail shooter.