I think Clemency itself is fine, the 4 PLD clear is more a problem with the incoming damage than PLD itself. If you can clear by spamming Clemency, then that means you can also just spam Cure II at those points, that's far too little damage in what's supposed to be a difficult fight.
The largest problem is still that the dev team views more healing as just higher damage, so we end up with a ton of mitigation checks but very few actual heal checks. If we can get more actual heal checks, that would also solve groups completely removing the healer role because then you'd actually need at least one healer to clear.