I wouldn't care if the person I dated wasn't a cosplayer. They'd eventually become one. That's the kind of effect I have on people. ;D
Video games are something completely different, however. I'd have to date a gamer, just because gamers think differently from other people. Their minds are different.... it's hard to explain, but that's kind of what I look for. Someone who has a higher level of thinking. Gamers have that.