I almost envy you if that was the worst thing that ever happened to you. Wiping due to doom can so easily be prevented by simply having a second DD standing ready for when the first one croaks. Some fights are simply not meant to be done solo/duo. It leads up to one of the best weapons in the game after all, I don't think asking to do it with two other people is such a bad thing.

Having said that, I do agree that the curing rate on Holy Waters or Cursna is surprisingly low, and I don't really see the point in it. Maybe just increase it to 50%?