I think motion controls won't save console shooters. Mouse is just better for first person, period. I'm not being elitist, I just think that each control option has its' own applications. Gamepads are better for platformers, driving and fighting games, joysticks are better for flight- or spacesims, keyboards just have a ton of buttons, and mouse allows for unparalleled precision and speed as well as much better menu navigation. It's not a question of skill, mouse is just better. Every FPS that fried to do cross-platform multiplayer between PC and consoles failed miserably, because PC players were just steamrolling their opponents.
Anyway, I would really like them to stick with conventional analog sticks for aiming. I don't think motion controls in their modern state can really be objectively better than any of the control options we have at the moment. Remember Steel Battalion? That game could've been actually playable if they stuck to a conventional control scheme instead of the pile of putrid snot that is Kinect.
Also, on the subject of Steel Battalion: I just thought of a way of saving the franchise. Re-release it on PC with full mouse support for half price. That's it, really. Don't know how hard it would be to implement, but it certainly might become actually playable as a result.