Yes, I'm definitely worried about it. I know MS claims they are taking steps to eliminate "false" reports, but what if sore loses just start reporting good players? One bad report is obviously not going to get you in trouble, but what if people band together to do it? I get hate mail all the time after playing COD, most of which makes no sense (I get called a camper when I am always on the move).
Another thing I don't like is looking for people who are frequently muted and punishing them. Maybe someone is just too chatty and I just want to mute them, but don't want to report them.
Plus, adding more complexity to matchmaking means more time to get into a game. I don't need MS to police the community. If someone is annoying, I mute them. On a rare occasion I run into someone doing something really bad, I set them as an "avoided" player. I probably have to do that once a year. For people who sing or scream during the game, there's always the quick mute option. I don't see the need for more than that.