Personally the only thing id like to see implemented right away is, CoS to generate enmity and id be fine with that only change.
Just to throw some ideas out...
Id also like Shield Swipe and Bulwark return to be valuable for endgame content, sure i could use it during Coil and Titan, but it really wouldn't matter if i did or didn't as rampart, sentinel, foresight, and shield oath take the bulk of the damage mitigation skill sets. So adding/adjusting stats wouldn't be an improvement or fix. Rather id like entire mechanic to be changed to make better use of the shield.
IE: While Bulwark is active, player will be granted charges for every successful block up to 3 (or 5), and you can use Shield Swipe (now off the GCD) to use those charges.
^ This change also gives 2 distinct pathways for players to shields among the 3, while Kite shields are still the best of both worlds, The biggest community change is how the player wants to fill their shield slot. Do they want more Mitigation (tower shield) which will grant them less opportunities to build Bulwark Charge, Or does the player like all the charges built, making him want the Round Shield over mitigation found from the tower shield.
Another is adjusting combos used in an off-tanking stance. Typically a level50 PLD off-tank will get on Sword Oath so as not to fight for aggro against the PLD MT on Shield Oath or WAR MT on Defiance. We are also forced to use Fastblade>Riot Blade Combo, with a combo potency of 230+50 that does generate much less enmity than Shield Oath>FB>SB>RoH. But even then we are still not to use our main tank combos regardless. Id love so that enmity % bonus is only granted on Sword Oath, and removes the multiplier on SB>RoH, allowing the player to still produce enmity based on damage, and not based on combos, so we can use FB>SB>RoH without creeping up to MT in aggro, making us throttling the DPS down for no real reason.
Another change id like to see is Combat Raise for PLD, with how our mana works and how much MP we use for Flash, raise is already an expensive spell to use, and realistically we would only be able to use it once or twice depending on the player so i don't think there is an issue with spamming raise. Or an Emergency Raise that grants 1 raise at the expense of 1/2 your total HP, making you really be strategic as to when to use it or if its viable to use it at all.