5 PLD suggestions that I think would be great
I - Divine veil should apply damage mitigation also for PLD and should not require a cure spell to activate on the party members.
II - The damage that you receive when using cover should consider your own mitigation, this way we would combine cover with HG, I think this would be a so cool clutch skill
III - Passage of Arms should be a circle where everyone inside receive a damage reduction, I also think the animation should be like a healer bubble where pld craves his sword on the ground and creates the barrier, it could stay as a stationary skill but with higher damage reduction since you are abdicating of doing damage
IV - Shieldbash as an ability, one with short cooldown and weak potency or longer cooldown with higher potency
V - The magic phase during the rotation should be different, Holy spirit been a weaponskill and the blades been and ability that it's only available when you cast Holy spirit, this ways we would be at least changing button during this phase instead of spamming 1 button, pretty much like GNB continuation works, also this fixes the problem with holy spirit been a spell.
Now the boring part, I've playing the game for a year manly as tank, and after start doing savage content I notice that pld requires a lot more of playerskill and battle knowledge to play optimally that other tanks, I'm not even entering in the damage discrepancy between these jobs, but I think PLD gameplay feels outdated, I hope SE makes some changes in the near future for my first class and the one that I most like considering fantasy roleplay aspect