Looking at various posts regarding party imbalances there seems to be a issue with the use of arc/thm/blm as the only DD in certain fights. One reason for this is due to the mobs using aoe too much on melee DDs. How about to give pld a aura trait which reduces the % of damage to those standing in close proximity based on the Pld's vit (but wouldnt affect any gla/pld in range).