I think a better alternative to trying to cash in on a limited gimmick tailored towards audiences on game consoles more than PCs would be trying to encourage a more universal gamepad option available for PC games. Nothing intensive whatsoever; simply easier access to gamepad input versus mouse and keyboard that is not an unresponsive, labyrinthine, trial-and-error conundrum. If a person chose to use the gamepad setup over mouse and keyboard, they could have a more smooth experience akin to the console counterparts of games, while still playing on a PC.
While most PC players will prefer the mouse and keyboard, I think that more people would be drawn to easier to access gamepad support that actually works, and across more PC games no less. I'm sure that more PC players would prefer a standard gamepad over a Wii-mote/Move clone, especially for practicality. Additionally this would make the PC game in question a more tenable option for an individual who is wavering on the PC version (but they are iffy on the control scheme) or their Xbox or PS3. Such a simple implementation could potentially more people to support the PC game market over a game's console equivalent. And Mouse/Keyboard preference or not, I think that most PC gamers would advocate means to expand the general PC game market and demand, as that would result in future interest and support by an increasing amount of game developers.
I suggest this approach simply because as it stands, the PC game market is occupied by PC gamers and the like in the first place. As I stated earlier, this is not exactly the target demographic for motion controls, as that is more of a console thing.
In other words:
1. General improvement and encouragement to use an equally viable gaempad input method for PC games.
2. Increase the PC game market's player-base by drawing in new customers, some of whom could be console owners.
3. PC games get more attention and support due to higher customer demand
4. Now if you want to start marketing some new-fangled motion-gimmick, at least the player-base is more diverse to accommodate this even farther leap from the standard mouse and keyboard control setup.