I think you should play a game any way you want. Motion controls can and will work for some people and not for others. If you want to get up and wave your arms around trying to hit someone, then go ahead, if you want to use the traditional controller then please do so. I think they can work for any game genre, including FPSs and RTSs. It seems to me that it would be fun to use them in FPSs and it can probably bring more precision to RTSs on consoles once you get use to it. I'm not saying they're the future, I just think it's about time there's a different way to play games now than using a controller or keyboard and mouse. But I do believe that the controls shouldn't determine the type of play style for the games, but they should develop the controls fully if they plan on having it as an option. Look at Killzone 3, they didn't develop the game for the Move, but they develop the controls to optimize the efficiency of use the Move.
"http://www.youtube.com/watch?v=levDGb1FY6E" is a video how the Move actually works in Killzone 3, I'm just too lazy to embed the video right now...