I totally believe that if the Revolution controller has a perfect gyro setup, it will replace the mouse/keyboard combo (or at least the mouse part of it) as the ultimate FPS control setup. A lot of you probably can't comprehend anything beating the mouse in FPS games, but a lot of people can't think of a better implement for RTS games, either. The touch screen on the DS is the reason all of these publishers are scrambling for PC-to-DS ports of RTS and Tycoon-type games. (I would kill for C&C Red Alert on the DS.)
The only thing bad about a mouse for first-person shooters, especially fast ones, is that if you need to turn around in a hurry, you need to pick up the mouse and drag it to the side again. You get the quick accuracy, but it's still not a perfect system. If Nintendo can get a gyro system working, you can just tilt the controller to the side, then tilt to where the target is, sort of in the same way as sight shooting with a light gun. The simplicity of a stick, with the precision of a mouse.
That's just my opinion, of course. It's pending what exactly the controller is, and how well the gyro feature is implemented, if there is one.