Those are my ideas so far:

1. For more mitigation and to make the block a stable value that can be more or less predicted I would like to see 3rd hit to riot combo that adds 15% and with additional perk 25% to block rate for 26 seconds (like Maim adds damage but with longer duration because it's 3rd not 2nd combo hit).

2. Sword Oath - in addition to receiving AA buff, increase the potency of the skills used under the sword oath by 20. It's not game breaking but it's enough to get PLD quite on-pair (but still quite under) with OT WAR.

3. Shield Oath - Make it available at lvl 30. So PLD can be as effective as WAR from the low levels onward. You can add both stances at lvl 30 and add the 3rd combo to riot blade mentioned in the n1 as lvl40 job reward.

4. Cover - redesign for any damage type.

5. Tempered Will - reduce the cooldown to 90 seconds and add 15% movement speed buff for the duration so this skill can be something else than only "heavy" remover while going from one fate to another.