As promised, it looks like Retribution has been nerfed, through a hotfix. The substance of the nerf is as follows: Divine Storm now does physical damage, not Holy. This means, among other things, it's mitigated by armor, which should obviously cut its damage significantly against certain classes.
Many people have noticed a similarity between this sequence of events and something that happened back when 2.0 was released, right before Burning Crusade. Divine Storm is the 51-point Retribution talent. The 41-point Ret talent, Crusader Strike, was pretty overpowered at level 60, so Blizz nerfed it, only to have to buff it back up later in the expansion.
The Divine Storm nerf is, similarly, in the context of level 70 balance. At level 80, where much of the Wrath balance testing has been done, Divine Storm may well have fit right in. Is an un-nerf coming when Wrath is released? Paladins can only hope.
Update: I am also told that they may have reduced the health/mana returned from Judgment of Light and Judgment of Wisdom by 50%, and reduced the damage of Judgment of Command by 25%. There still isn't a blue post that I can find about any of this, so it's hard to confirm -- can anyone confirm/deny the Judgment changes?