I'm the healer. I'm never asleep (except this one time at 3AM in Haukke, but let's not go there). That boss has consistently been the absolute hardest to cure for of anything released so far because it just keeps doing 300-400 damage. Maybe my tanks are idiots? Could be that. I tend to see no dodging or stunning or anything of the sort, just straight tanking to the point where spamming Cure II is the only option. I actually love the final boss of the dungeon, it's the type of thing I play on healing classes for. I think it'll weed out the decent healers from the ones who spend half of their MP nuking with Stone II.
And yeah, it probably just depends on party composition and the quality of players. I made that example earlier in the thread about an idiot being someone who AOEs Sleeping monsters over and over despite being told not to thinking it wasn't going to happen to me. It happened. On the other hand, I had an absolutely amazing time helping my friend in Hala with it, where everyone knew their jobs, the run was very fast, and we were all friendly and talkative. I also really like helping with Sas, since people seem to genuinely want to know and learn.
Duty Finder is so hit and miss.
Belated Edit: After pretty much fully exploring everything at this point, it's making it a lot harder trying to decide on where to start my character. Because damn if Limsa isn't looking appealing over Gridania - particularly if Arcanist can be used as a healer. Ul'Dah's low-level areas are hideous, but the town is great.