Conditionally, I hope Requiescat will out damage CDC. Not under normal conditions, but under the condition that you are fighting something with extreme physical defense.

I agree RDM does fine with Double attack, but Crit is not so easy to come by for consistency, outside of aby. There are only a small handful of items that a RDM can acquire.

CDC could be beaten by a well designed Elemental WS. At least on RDM. BLU and PLD, probably not. They don't have the same access to MAB as RDM.