As someone who plays a lot of AST and other healers, I can assure you I'm always parsing my dungeons to know who will benefit more from cards or who is worthy of a rez if they do crap (especially for void ark).
And I can assure everyone here that everytime you'll go in a Ex farm group, Down group or other same-type content, there will be a parse running, and if you under-perform, you'll get the boot.
It's already something vastly implemented, an in-game would atleast put everyone on the same level.
For the personal parse, well, it's pointless. I can do 500 dps on my character on a trial, next week, I do 600 dps, yay I'm good, meanwhile other players do 1k and I'm unaware of that.
Those numbers only have value if they're put in comparison with each other.
And for people complaining that it would be an attack against casual players, I'll have to ask, why do casual players can get a free pass to underperform?
One player not doing its job means 7 other players having to compensate, and when you're trying a down for a primal/savage and keep hitting enrage or getting short to it because one player is doing half its job, then you can atleast show him the crude reality of the numbers.
And I can assure you from experience that a lot of players I know has been improving themselves once they started using a parse, because they saw that they had a lot of improvement available.
Someone that don't want to try doing the best it can for a group is just a leecher, and you don't need to play 24/7 to be good at your class and improve.