Basically, like Kachi said, you make different reqs. and different caps per job.
As a DRG, I should get rated on buffs or debuffs or magic. It should be pure dmg. So, give Drg a much higher cap on Phys Dmg.
Give all jobs a hard point cap, give every dmg a value, set different caps based on what the job can do. Drg would only have 1 pool to cap, so they should get that faster. I'm explaining this poorly, but it's a really easy concept. Have the system in place where everyone can cap within the same amount of time, and adjust as you go based on data received.
Again, this would take a level of effort we are not used to from SE.