DPS display could easily be solved with a system already in game.

[Atmora]

because then u will have ppl raging that brd dont use song because they parse lower

that melee ignore mechanics in order to keep Dpsing

that blm/smn aren using aoe when they need to focus target to pad metters

or hell that pld/war ignore tanking in order to keep dpsing to feel like a wannabeDD

Meters even at the end of the instance can cause havoc , we have seen it before

BLM and SMNs would never chose single target over aoe because aoe rotations do more dps though, and good palladins/warriors spend as much time optimizing dps as safely possible. To top that all off you're also supposed to learn to what extent you can disrespect mechanics as monks, black mages, etc. in order to output optimal dps.