[Discussion and Feedback] Incoming damage vs. Utility

[Absurdity]

Swapping was one way to deal with it. Trials back then also created a necessity for tank swapping as well due to stacking debuffs generated by the boss.

Not just trials back then. I remember tank swapping simply because my co-tank still had all their defensives, and I would've had to either swap to Defiance or pray, as late as Stormblood.

It was really only with Shadowbringers that this started to shift heavily. Bosses started doing so little tank damage and busters were so spaced out that the "main" tank could cover every attack with just their own cooldowns.
Which is why a lot of bosses nowadays either give a vuln up debuff to force a swap or put a buster on both tanks, because otherwise the "off" tank would just be sitting on their defensives the entire fight.