To be fair, Wii was a bit of a gamble. Not knowing if the wiimote would catch on or not they decided to go with hardware that wouldnt lose them loads of money even in case of a early price drop. For it's time Wii turned out to be a great gamble and Nintendo probably made a killing on it.
For WiiU, I hope Nintendo doesn't do a Wii again and goes as cheap as possible on the hardware. At the time it worked and even I didn't care it wasnt the most powerful console. But wouldn't buy a ps360 level hardware WiiU. As others said before, it would probably take more effort to create a console that isn't more powerful than one that is. Even if considering hardware must be cheap.
But Iwata said WiiU won't be such a cheap console right? Even with the tablet controller if they aim for 300~400 euro's it must be possible to put in some decent hardware.
edit: even taking just standard pc hardware, a A6, 6870 and 4gb of ram and mianboard will come at 290 euro's at retail. Now thats retail so buying directly means you can cut atleast 90 euro's, even more when you take into account that a lot of stuff is redundant and won't be needed on a WiiU mainboard. So worst case scenario you pay 200 euro's for the basic hardware. At my part time job we sell tablet with 8'' screen, 4gb memory, 1ghz cpu, the lot for under 80 euro's (and the place I work at isn't the cheapest around). The controller can't be costing more than 30 euro's? Aiming for 300 euro's, that leaves 70 for the case, psu and diskdrive and cooling. Shouldn't be impossible.
For 300 euro's you'll have a system running circles around ps360, could easily do 1080p, hell it might even run ps720 ports without too much trouble. Nintendo making no initial profit or a small loss on the hardware, I think this would make for a great system.
Than again, Nintendo might as well ask AMD and IBM to butcher even their slowest hardware so they can end up with a ps360.