Nintendo - have they forced themselves into a corner?

Nintendo took a gamble with the Nintendo Wii, and in particular the Wiimote, last year when it unveiled it console. The Wiimote manages to set the big N's console clearly aside from the compeition, and like the DS, it managed to draw people into gaming that previously hadn't even considered playinf videogames.

But where do Nintendo go next?

Have they boxed themselves into a corner by adopting such a radical controller design? Im wondering what they are going to do for their next console.

Do they keep the Wiimote idea and simply upgrade the power of the Wii?
This obviously isnt the innovate approach, but it means that games could have better graphics and the machine could process data much faster. Maybe this is the right way to go - get an audience hooked on the controller, and then simply upgrade the power of the console.

Do they go back to a standard controller?
Maybe the Wii doesn't become a hit. Perhaps Nintendo will have to back down and go back to a more generic controller style in order to compete with Sony and Microsoft. Although I find this very unlikely after examining the initial success of the Wii and the failure of the gamecube, its still a possibility. Albeit it would mean them backing down majorly after putting masses of faith in their new approach.

Do they innovate again?
Will we see a new controller? Previously motion sensing hadn't been cheap enough or powerful enough to include as the main feature on a console. Perhaps in 3-4 years time, a new innovation will hit us, or an old innovation will be cheap enough to mass produce for their next console. But will the new innovation be too complex for the niche audience that hadn't played videogames prior to the Wii?