While GoD was super difficult it wasn't the main reason for the population decline. WoW had just released that year and was Everquest's first real competitor.
It was a pretty big reason. The top guilds had all farmed the heck out of PoP, and GoD was impossibly difficult so there was nothing to do for them.
The philosophy for the vanquisher (and challenger for group missions) needs to rethought. Instead of being a few achievements with typically goofy restrictions they should be a true hard mode with a singular achievement per event that increases the difficulty in a way that builds on the core concepts of the event along with being stat-based. Mobs have more HP, deal more damage, spawn more and the event timers are more restrictive and punishing.
There have been some good Vanquishers and some bad, the bad are the ones you gain by just doing the raids, the good are the ones where you have to change your strat to get them, sometimes this makes things harder. I remember doing the pig zone, can't remember the name of the zone, we did a mission and got an achievement for not going in the pools, all 3 of us in the group said, "what pools?". Sometimes it feels the achievements that are added are just to give us an achievement not to actually make us do something we wouldn't usually do.
