So this game has dps checks but we can't talk about our dps in game?

[Kleeya]

It's not that difficult to discount the tanks and shift everyone along two places.
Aggro has a direct relationship to damage dealt, so you can absolutely just the dps output of the four dps jobs by aggro alone.
It's only the tanks, and sometimes the healers, who are outliers.

A dps single targeting in a pack will be shown in lead on his target, while doing less global damage than the other dps using their aoes on all the mobs. Same with bosses and adds phase, a dps being in lead on the boss will drop in aggro when switching to the adds, compared to someone who will keep single targeting the boss instead of playing properly.

Or you can be killed by your teammates fleeing you when a stack marker appear above your head, and become last on the aggro jauges when ressurected, while still being in lead in dps because you know your rotation and the others not.

Aggro jauges are just that : aggro jauges. Don't mistake them for an accurate description of a player's prowess.