I can honestly tell you that Clemency is at best mediocre. I am 100% certain that all high DPS PLDs (see fflogs) don't ever use that skill unless if there are downtimes or when 1 healer is down and you are forced to use it to recover. Or maybe if your healers are so bad. Other than that? PLD just dps away.

The reasons why PLD is "better" vs DRK in this current patch is because of safety (instead of more damage, in which DRK excels in) from stacking RoH and Monk's DK in 1 boss, Divine Veils and Hallowed Ground cheesing. Clemency has nothing to do with how much better PLD is atm, almost nonexistent if I might add.

If the argument is about Clemency enabling healers to do DPS more, it's bullshit. Why? Strong WHM = more DPS.