It's on par with the other variant dungeons. A boss that takes 8 minutes to die is hardly a "sponge."
And it's way worse in parties, as I've yet to be in one where people had the proper actions for their jobs... I think the last boss in my last party last night took 15 minutes to kill, so I've decided to stick to solo after that (we had a tank and healer yet everyone but me had shield and heals as actions...).
