Denying people who want it for the fear of people abusing it means we wouldn't have any of our features currently in game.

Fact of the matter is, people -know- when DPS, Threat, or Healing isn't enough. It usually involves a wipe, or a far more strained encounter than it's supposed to be. And when they -know- it's not where it should be, it's not a huge step to see who's dragging everyone down. (Aggro meters, while not perfect, show a very good indication over a few minutes of how hard everyone is pushing)

So, no, your fear of parses is irrational because the situation -already- exists. There are already third party parsers people use and will 'dps shame' with. The only thing an official meter does that a 3rd party one doesn't is eliminate the set up, potential inaccuracy, and provide easily access information.