Third person shooters are not bad, in fact I think they are pretty good. I think third person shooter develop a far greater relationship with the character in the game. For instance when you play a FPS you only get to see the hands character most of the time and that makes it kinda impersonal. Sure you should feel like you are playing and you are the character but with TPS you get to see the character all the time and its surrounding.
Im not saying COD really needs this TPS option, I mean COD has been great and the formula can go untouch a little longer. TPS are like watching a movie or reading a book to me, for example uncharted has to be one of the must play games in the ps3 and its a TPS and so its Gears of War on the 360 and even metal gear. So I think both views acomplish diferent things one can be mindless shooting and having fun while the TPS are more to tell a story, FPS can accomplish this too and make it all the time. TPS is in the end merely a tool to accomplish a perspective in the gaming industry.