What happens when.....

[Syzygian]

You linked to this in another thread referencing it as a compilation of things that PLD lacks and I wanted to mention something along those lines that may not be completely obvious between all 3 tanks.

So in terms of mitigation, assuming fights with equal parts magic/physical damage, I feel all the tanks are very balanced in this regard. DPS is another issue entirely though, as has been discussed ad nauseam on these forums.

So DRK and WAR both have tank stances and they both have buffs that they can maintain with 100% uptime to counteract (partially) the damage penalty of their tank stance.
DRK: Darkside (-20%, +15%)
WAR: Maim (-25%, +20%)

DRK and WAR both have extra fluff damage which is usable regardless of stance. With WAR this is in the form of its powerful buffs and with DRK this is in the form of a surplus of off-GCD damaging abilities. (ppm= potency per minute)
DRK: Plunge (400ppm) Low Blow (200+ppm) Salted Earth (787.5ppm) Carve and Spit (450ppm) Dark Passenger (450ppm)
WAR: Berserk (+50%) Internal Release

DRK and WAR also have a form of supplemental damage which contributes to their MT DPS.
DRK: Reprisal/Low Blow procs
WAR: Unchained

PLD has NONE of this. Fight or Flight is a simple offensive cooldown that boosts damage yes, but it is unclear wether this was intended as a partial counteraction to the tank stance damage penalty, as free damage like Berserk or DRK's oGCDs, etc. Whichever one it was intended as, it leaves the other department empty. PLDs oGCD damage is minimal and at the same time has only 1 offensive cooldown. If Fight or Flight was a 60s recast it would counteract the Shield Oath damage penalty (+30% with 50% uptime is 15% overall thus bringing the damage penalty to -5% like the other two tanks) but its 90s, more like Berserk.

The only thing PLD and the other tanks share in terms of DPS is the bonus of their DPS stance.
PLD: Sword Oath autos
DRK: Blood Weapon (+10% attack speed, more MP and thus more 400 pot DA Souleaters)
WAR: 5% Deliverance, Fell Cleave

Even here PLD is underwhelming. Whereas WAR and DRK share many of the same elements to their DPS toolkit across their stances, and those elements follow similar patterns, PLD's feels utterly incomplete in comparison.