12-15k burst within the duration of their HoJ is not what they were capable of. The difference is like being hit by a 2 seat ford pickup and an 18 wheel semi.
That kinda sounds like a complaint about ret paladins to me. To which, I say, get over it. The same complaints were raised when Burning Crusade replaced Vanilla WoW. Ret paladins haven't changed all that much, they are still able to output high amounts of damage in a short amount of time. That is what the spec was designed to do.