I actually wouldn't mind if the game tells us after a duty is failed, how we performs relative to the officially tuned average DPS.
For example if a fight requires DPS*4 to do 750 dps plus tanks*2 to do 350 dps (and healers*2 to do 0 dps, obviously), then when the duty ends, we each personally receive a report on our performance saying things like:
- (120%+ of threshold dps) "You did great! x% over the minimal dps!"
- (80%~120% of threshold dps) "You did fine! But there's room for improvement!"
- (40%~80% of threshold dps) "Nice game! But with some work you can show the true power of your class/job!"
- (-40% of the threshold dps) "Perhaps your current gear is not suitable for this content. Next time we shall prepare better!"