What will they plug into the Wiimote next?

[Grey Acumen]

Yeah, basically teh problem comes down to the fact that too many peripherals will cause a lack of support for any of them.

Personally, I had an idea for a rumbling nunchuk with a built in microphone, as well as having a second motion sensor that was at the end of the piece that plugged into the wiimote, allowing for a sixaxis-like effect on the wiimote whenever that upgraded nunchuck was plugged in.