LevelUp interviewed Miyamoto shortly after GDC, and the interview is up for view on their website.  Most of the interview is discussing Miyamoto’s approach to gaming, but he also challenges 3rd-parties to take advantage of what the Wii has to offer to developers:

We’ve talked about how videogames have been advancing as technology advances. We’ve questioned whether there was really a need for graphics to continue to improve the way they have and processors to continue to improve the way they have. But we didn’t really have any concrete examples of how you could forego those types of advances and still have a revolutionary new gameplay style. So I really felt that now that we had some concrete examples of some of these ideas that we’d been talking about, that it was a good time for me to talk to the developers themselves about some of the ideal ways that we see creators can interact with technology and find different ways to use technology to bring their ideas to fruition.

Source: LevelUp