Well it isn't necessarily a confirmation, but Ubisoft says they are developing it on high end PC's and next gen, and after the team is gonna look and see how fits for the older generation here.
They also said that the game is already up and running on the Wii-U and they are looking to see how they can use the gamepad.
There are several good things you can take from this. First of all, the Wii-U version is being ported right from the high end PC version, as they haven't started development on the current gen version of the game. Also Ubisoft has already got it running on the Wii-U, meaning that the Wii-U can handle next gen engines without too much troubles. I am very excited for this game and think I will end up buying it for the Wii-U. I will have to see more, but I'm glad to see the Wii-U version of the game is being considered a next gen version, rather a port of the current gen version. Hopefully this will push the Wii-U and I'm curious to see how the gamepad will enhance the game. Although the delay for Rayman is pretty ridiculous, I'm glad Ubisoft is taking the Wii-U seriously. Hopefully the rumours that Rainbox 6 and Splinter Cell Blacklist are coming to the Wii-U are true. I saw Splinter Cell Blacklist for Wii-U being available for pre-order on an online futureshop/best buy site, so fingers crossed.
Anyways developers of Need for Speed U have also released screen comparisons of the Wii-U version vs the Xbox 360 version. The graphical difference is very noticeable. I think this is proof the Wii-U is a lot more powerful then we think. Its surely not a PS4, but I think it should be able to run everything next gen. The Wii often couldn't run engines like the Unreal Engine 3 or Capcom's MT Framework which meant a lot of developers wouldn't bother porting games since they would have to create entirely new engines. Luckily the Wii-U already is confirmed to be able to run Unreal Engine 4, Cry Engine 3, Ubisoft's new engine used for Watch Dogs and the new Frostbite Engine. This hopefully will translate to more third party releases on the Wii-U, even if the graphics are scaled, the process of porting should be a lot easier for next gen developers.
Here are the screens for Need for Speed U vs the 360 version.