It would require a major change in gameplay, because it would need decoupling the direction you face from the direction you aim.
Which, btw, could be a downside of all FPS games when using a pointer like the wiimote or a wand: it would make circle-strafing very hard. Metroid Prime 3 had a lock-on function that helped. I wonder how it will work in "The Conduit".
For all the claiming about pointing being the ultimate way to have FPS controls on a console, that's eminently true in on-rails games, but poses quite some problems when you want to combine it with free motion and rotation of your character.