A damage party-buff doesn't fit in line with what PLD is (but I agree that it needs utility).
A 2019 update on shields would be nice--
Make it so striking a shield lessen the boss's physical/tp damage, even if it was a short term debuff (say 10 seconds). Paladins would feel rewarded for blocking more, because the melee are safer from damage.
Make Rampart a stoneskin granted to the party, 10% of the Paladin's Max HP.
Make Shield Bash open up a boss to damage, causing it to take more physical damage for 15 seconds? This would be a thematically acceptable way for the Paladin to buff damage.
Like Rayke and Gambit, the debuff from striking a shield, and from Shield Bash, would benefit the entire alliance.
Make Cover work regardless of position. Make it behave like accomplice.
Buff Flash's base magic accuracy. I missed the days when it would land on everything but Byakko, and last for a few seconds.
Flashga would be fun, but hardly necessary.
Reprisal could be reworked entirely to do decent damage, and detached from any damage cap. Make it scale with number in party.
Make a paladin-zanshin, when the PLD blocks, they have a chance to swing again.
Paladin will never be the damage dealer that RUN is though.
(None of it will happen. The days to fix PLD have long past, and it's at least serviceable, unlike the state they've left other classes for years.