Honestly, the same discussion continues over at the DPS forums. And just as I said there, we're all quite aware of what can possibly go wrong. Why don't we instead look at what might go right?

Where would any reasonable, responsible player NOT benefit from a tool that simply would allow players - individually - to know exactly how well they are/aren't performing, and perhaps learn to improve?

It's late; please go read the "Real Problems with Parsers" topic in the DPS section. Many good points are made there.