The more I think about it, I really think its going to be gyroscopics like everyone has expected. The revolutionary part will be in how they are used.
1. people can use it for basic character control. This has been done before and isn't really that intuitive, so I don't think it will be it.
2. You could use it in place of the c-stick in many instances. For example, looking in a game like Metroid prime. You control with the stick, but the way you tilt the controller decides where you are looking. I think this could be a cool bonus feature.
3. The key feature (much like the mouse idea) is you use as you would a touch screen. I offer this link as an example.
http://www.gyration.com/ultragt.htm Using a system like that, people could play games like RTS with a really inuitive feel. Make the controller break in half (with the gyration part coming off) and it could make for really comfortable, laid back, one handed gaming. Perfect for turn based rpgs and strategy games, as well puzzlers and 'non-games' that will help pull in the non gamer.
If Sony or MS hear that Nintendo is putting a gyroscope into their controllers, they could throw one in really quickly.... Even if it isn't as sophisticated a plan as Nintendo's, it would still take the uniquness away from Nintendo's console.
How much you want to bet I (and the many others with a similar idea) am right.