Wii U's doing better than Gamecube, isn't it?
Nintendo can take a hit after the wonder that was Wii. But let's face it, a ton of people bought Wii and played it for a couple of weeks. They got their friends to buy one too, with Wii Fit or something, and then never play it again*. Nintendo's not getting Wii-like sales unless they trick people into buying something like they did with Wii.
It seems to me like Nintendo would be too stubborn to partner up anytime soon, though. But if they do, let's hope it's with Sony? I would actually love it if there was only one console, with an amazing app store. People would have to stop the flame wars and argue about which games on the console are better instead.
* Not saying the Wii game library sucks. It really doesn't, but people aren't aware of this.