If you read past the confirmed dev kit specs (developer confirmed from Nintendo's SDK) in the article and read about the features of Wii U's GPU you can understand how superior it is over the current HD twins. It basically comes down to the Wii U having a GPU using DirectX 11 features that are not possible on current systems.
Optimized post-processing effects – apply advanced lighting techniques to enhance the mood in a scene
High quality shadow filtering – no more hard edges on a shadow, see shadows the way you would in real life
Depth of field – use the power of the GPU to have more realistic transitions of focal points – imagine looking through a gun sight or a camera lens
High Definition Ambient occlusion – incredibly realistic lighting and shadow combinations
This confirms that the Wii U is a next-gen machine not in comparison to the Wii but in comparison to the current HD systems. All next-gen systems will have graphics cards that have the same/similar features from...