The OP's approach to this issue is a bit disjointed, and hard to follow, but he's right to say that PLD has close to no advantages from a strictly pragmatic point of view.

PLD dps is solidly the lowest among MTs.
PLD dps is solidly the lowest, though not to the same extreme, among OTs.
PLD unique CDs are less practical than the other tanks:
Cover has limited to no uses in current content
FoF is great, but is nothing compared to Maim and Darkside
Bulwark is a wholly unreliable mitigation CD
Bulwark and Sheltron are useless in fights where the boss doesn't deal physical damage
Tempered Will has the same problems as Esuna in that there's no consistency when it will be effective against the same effect across different fights
Clemency is trash with barely any practical application
Awareness is solidly meh; you'll never actually know how many crits were avoided because of it

On top of that, several PLD abilities have severe QoL issues:
HG is overpowered and has a 7min CD to compensate; this is HORRENDOUS for progression content as it adds an extreme amount of downtime when wipes happen
Goring Blade is the PLD DoT, and it takes 3 GCDs to apply compared to the 1 GCD for WAR/DRK DoT
PLD still, STILL has zero AoE damage outside of CoS

SE needs to do a ton of work on PLD. The fact that we have a shield accounts for nothing in the face of how much better WAR and DRK are against bosses.