Yeah, that makes a lot of sense! I think you hit the head on the nail. I had thought it was going to be like the EyeToy for PS2, but I never thought of the Wiimote/mouse analogy. It seems like such a simple concept now that you pointed it out.
The Wiimote/Nunchuk combo is really, in my opinion, superior to a keyboard & mouse because it will replicate (to a degree) an actual weapon, tool, etc, while the analog stick of the nunchuk allows you to vary your character's movement (fast, medium to slow), rather than the "stop-or-go" approach of pressing buttons on a keyboard.
I still wonder, however, how Wii will know where the center of the TV screen is, since some people will have it above or below their TV? Do you, or does anybody think it figures the center in the same exact way a mouse does? Also, do you or does anyone think we'll see Wiimote/Nunchuk knock-offs for the PC, or will everyone stick with the status quo?