There is a relevant interview of Richard Mrks ingame spy. He's one of the creator of the Eye Toy.

Game interfaces often get the shaft. Developers invest tons in graphics or sound or physics, but nobody ever invests tons of time into the control scheme. Often people don't even really think about it. Game controllers are ubiquitous. You push a button, and stuff happens. But the interface is literally a player's connection to the game: it's where the action happens.

And after a couple decades of stagnation (game pads are basically the same as they were for the NES, save for more buttons) we're finally on the verge of some crazy new technologies for how people interact with games. The Eye-Toy is leading the way, proving that there's an opportunity for new concepts to hit mainstream.(...) Marks started firing up demos and showing what new technology was on the horizon: Head Tracking (...) Future Cameras and "Per-Pixel Distance Measurement, (...) New Interfaces for Handheld: Adding a camera to a handheld can open up tons of possibilities. Dr. Marks, who used the PSP in all his examples, is particularly excited about the idea of using a handheld as a "lens" to view the world. In other words, stick a camera on top of the PSP facing out, then look "through" it (at your screen) at the real world but with digital stuff overlaid on top of it.

Why do I blog this? I always thought the game designers should get rid of the standard game controller (or at least try to innovate a bit about it). There are some nice things showing up here, but I still tend to think it's too technology-oriented, they really need some end-user perspective.