While the camera-based motion-sensing tech shown by Sony and Microsoft during E3 definitely impressed a lot of gamers, Nintendo president Satoru Iwata had more of a "been there, done that" attitude.
Speaking to the Financial Times, Iwata said that they've actually already made experimental games controlled by camera-based sensors. That tech was eventually rejected, however, since they got better results out of the accelerometer-based tech now used in the Wiimote.
Iwata also seemed to welcome the competition, saying that he was happy that motion controls are starting to become an industry standard. "Companies whose people said that motion-sensing wouldn’t work are now proposing motion sensors," he said.