There is always at least one aspect of their systems that's lacking, though. The SNES had a slower CPU compared to the Genesis, though I s'pose it made up for this with the GPU. The NIntendo 64 didn't have a sound processor, and of course the cartridges bottlenecked the whole system anyway. The GameCube also had smaller discs, and I believe it has less RAM than the other consoles.
I just don't see Nintendo making such a huge leap over the Wii, especially since they are once again focusing on the controller over the system specs, one which looks like the most expensive controller ever produced for a gaming system. So I'm quite certain that at least one aspect of the Wii U will be lacking, but time will tell what that is.