After taking a brief look at what people say about the said dungeon I have been hesitant to unlock it, because I don't want to use Duty Roulette to end up in a dungeon that is hard for no good reason. I assume I'm doing myself a favor. And from the looks of it, it doesn't look like Square has any intentions of nerfing this dungeon (unless I'm missing something), therefore I will keep the quest unfinished.