The community around high end play is already toxic. All an in game parser will do is make it more toxic, but not much more, since it really can't get that much worse.

I don't mind dmg meters, and I had the best mod for keeping track of my own stats in WoW, so it's moot to me. I just know it will add toxicity, period. Now, it is a useful tool for PF, because you can flat out say your requirement for dmg/sec max and actual, and you can then kick people with a clear conscience for not holding up to the bargain they signed on by joining. DF is harder because it's 4/8 random people, and there really can't be expectations at that point. But PF and pre-made...yeah, kicking wll be a lot more clinical and emotionless, since numbers will back up whether you are pulling your weight or not.