I barely see a point in making "the turning" look more natural by slowing it down. I mean, how natural is the fact that your character can run with a 5 kg automatic rifle, 6 x 30 bullet magazines, 4 frags, a 9mm pistol with additional 4 x 8 bullet magazines and a torch from maglite(c) for 30 minutes?
I think that the attempt of Operation Flashpoint, or ArmA, was a good one, by making the gun and the view slightly detached, but once again, that made the game good ten times harder, thus resulting in that function being turned off right after adjusting the graphics.
Now back to the topic, I think that FPS could be interesting on Wii because of the more recent features included. For example close combat or frag throwing. Of course the actual shooting bit would be miserable as usual, but it could be compensated by other features that do not work so well with the mouse/keyboard.
PS: Note that I never said that Wii was good for FPS.