The main reason to stack Enmity atm (imho, of course) is due to the HIGH amount of mobs with hate-resetting moves in Abyssea.
So even if you were doing everything you possibly could and the mob uses a TP move that resets your CE and VE to 0…
You better hope you have some Serious Enmity to stack on that Flash or you and your PT are outta luck.
I think if there were less mobs that could reset enmity at the blink of an eye PLD would be more viable then as a Main Tank again. I suppose it is how it should be however and PLD has been reduced to a puller/DD/backup_healer for the time being.