Job disparity can exist just fine without imbalance.

A DPS/offensive tank and a defensive tank can exist just fine in even the current meta where DPS is the most important thing. You can even pair defensive tank + defensive tank and reach the same raid DPS as a offensive tank + offensive tank pairing.

Jobs can also have different roles. It's just that in the end, the cumulative raid result needs to be the same.

Nobody should have their progress gated behind their job choice. During this raid cycle, it clearly was. If you didn't level a DRK/WAR to 60 and gear it with eso, you (and even worse, your 7 raid mates) were behind in progression by weeks by default.