I believe Bahamut Coils difficulty is for that, a chance to appeal to Hardcore players. We did most of the Bahamut place and I don't have anything to complain about it, its perfect balanced on party behavior, its something you have full control of. But RNG is just a way to make you lose to something you don't have control.I see no reason in doing more than 20 times a dungeon for no indication of whats happening.