Far from a gimmick. You need to try it. My girlfriend who is not even a gamer has put down hundreds of hours and she didn't even want to try it at first.
When the first ps3 motion controllers came out, we played <that game with the swords and shields> until our hands hurt. I'm still surprised we didn't break any furniture or the controllers.
Lasted like 3 days though.
The fact that I do actual sports, including stuff with swords occasionally, might contribute to my "gimmick" opinion :)
