with the price of high def Graphics cards, if they made a system that was only on par with the PS3 or worse, the 360, they will not gain superiority over the 360 or PS3 with just their new controller. they already flopped with the wii with hardcore gamers from having poor graphical power. currently, Gaming is reaching its peak of graphical power, its not there yet, but its getting very close. the Wii wont get people to buy their new console for just the new controller, and Im sure they know this. they said in the interviews that they do not know how much stronger the game will be, but you have to remember, that they are probably taking into account COMPUTER graphics aswell, which they will probably be on par with. But with the, how many years has it been now?, and as that interview states, it would be odd if they kept the graphical power at the level of shit of the failbox 360.
remember: the 360 runs on only 2 cards that were outdated when put into the 360 at launch, let alone now. the 360 does not have true HD even. the PS3 is closer to true HD graphics, but neither of them can process DX11, which, the Wiiu, will more then likely be able to.
I am assuming, that the Wiiu will probably have something equivalent of the Raedon HD 5xxx series, as they are down to about 100 canadian now, and FAR, FAR outclass the 360 and the PS3.