In my humble opinion, there are a few changes that I'd recommend considering:

1. I think Ranged DPS should have their free additional action Phantom Dart swapped with Drain. That way they inherently always have the additional regeneration.

2. Reduce the number of potions Tanks can use from 3 to 2. (They are already quite tanky and with slight additional tuning to their defensive skills would still be more than resilient enough.)

3. Increase the number of potions for Ranged DPS from 2 to 3. (This in combination with # 1 would allow Ranged DPS to be much less guaranteed kills than they currently are.)

4. Increase the cooldown on Chiten and Riddle of Earth from 15 seconds to 20 seconds.

5. Tune potion use "wind up" to occur faster to prevent strange server tick issues.

6. Bring back AST's infinite benefic 1 loop mechanic and further buff SCH so that each healer is unique and viable.

7. Slightly reduce MNK burst damage.

8. Extend / enable Blood of the Dragon for DRG when completing their basic combo in addition to starting it.

And more. These are just a few ideas I think could improve the current PVP meta.