Let's a look at another fight, a fight apparently so difficult that it no longer exists in the game, T7:
In T7, the main feature was that there were many instant kill mechanics, in which your teammates kill you. As everyone knows, if you get petrified, then any additional damage instantly kills you. Cool so far right? We can just avoid being petrified. But only one mechanic can you even save yourself from being petrified (petrifaction). Cursed voice and shriek petrified everyone but the user. You also have someone else petrify a renaud before it mauls your face in. First fight in the game where you actually have to trust your teammates to not fall asleep in the fight. Sure there were other stuff in the fight (renauds, dps checks, etc.) but nothing like trying to avoid death every 20 seconds from your own teammates. However in the end, all of these were handled simply (everyone face the edge, designate a ranged to stand far from boss, build The Great Wall of Renaud, shrieked person always run to the same location, etc) and the randomness seemed kind of a non issue. Once again this fight did not require vast amount of skill to complete (and now boss gives you a rope to hang her since none of the above even kills you).