If SE's attitude toward class balance is "Hey, we said this is hard, so if you can't clear it on a certain class that's not our problem!" then I'd like them to be up front about that so that people have a chance to unsubscribe from the game.

The chances that they feel that way are close to zero, and the chances that you are actually literally unable to clear the fight with a DRK are about as small, but I've yet to see anyone even come close to saying anything like "Actually, DRK might be better than [PLD/WAR] in this one!" and can't really imagine a situation where that would be the case, so hopefully that (combined with plenty of feedback elsewhere) will be enough of a shock to SE's sytem to do something about it, sooner rather than later.