I'm not a bad player, but the vault final boss does need some adjustments. This fight is a bit random on where/who he targets his ground aoe and it can make it hard/impossible to dodge the knights. Who do infact cause a bleeding debuff. Coupled with if you have lag, this fight can be near impossible because this boss spam effects like a bad blm in ff11. I have had occassions as a healer where my mp drained @ the boss @ 50%. And this is with using mp refresh skills. Its npot a hard fight, just can be a very random lag fest.
Also please stop blaming nerfs on bad players when the community is part of the problem. In ff11 people was more then willing to explain fights and each person roll during said fight. Here people go "read a guide" "watch a vid". Issue with this is guides and vids don't get updated as the mmo ages, also what "guide" should a person read there are tons of them all with conflicting stratagy. What "vid" should a person watch? There tons of them with conflicting strats.
Also, people don't give others a chance to learn, I recall df pt after df pt as a fresh pld and being insulted, my family insulted, being told to quit all because the pt was pushing me to do things i wasn't ready for. And I'm austistic so this stuff can really put a damper on me learning, or wanting to play this role. Infact i switched data center because of it. I had 1 case where a known troll on my server was in a df group, and kept tellinbg me to mass pull mobs in halatali, as a lvl 23 gla. I looked at him and go are you crazy? I was already having some enmity issues from prepull casts, and post pull casts w/o being able to build up enmity.
Then all the mob skipping it can be a bit meh when trying to really learn/level your class, plus all the loot that gets skipped. Instead of having a "get it done" try to consider the other people in the party.
there are no such thing as bad players, only inexperienced players or trolls.