In youtube you could see a year ago (maybe now too) WP speedruns with no doors, the tank pulling everything and then all the mobs resetting at the entrance of the last room and going away so you didn't have to kill them. Then they put doors or other methods to avoid that.

Brayflox HM has doors so what we call speed run is not a total speed run, the developers knew where they put the doors and how many mobs could be pulled together. Brayflox HM appeared at the same time with the Animus update and everybody needed to farm a lot of tomes, so speed runs were all the time at PF. And certain jobs were not wanted, there were conflicts among players, some never wanted to go to Brayflox HM, and a there was a lot of drama about speed runs. This made developers make doing huge pulls and lock-out tecniques more difficult in later created dungeons than what they had done previously.

It seems it works, since, though people discover ways and new methods to do quicker runs, there is no drama about speed runs in the newer dungeons as there was when Brayflox HM appeared.