Guild Perks in WoW were dropped in Warlords of Draenor, along with 90% of anything that was fun. There were 10 million presales of that expansion before it opened. I was a Beta tester, the only one in my guild for WOD, and the testers told them and told them it wouldn't work. The loss of those guild perks was huge, since players could no longer run through a dungeon with their friends but were tossed into a quagmire of some of the nastiest people on the planet (who all had microphones). They lost a million subs a month until they had less players than they had in the first year, 2004, and guilds became miniscule, with any hardcore raiders moving into massive guilds and the average guilds dissolving. WoW then became known as "Raid or Die", and everywhere I went in Elvenar I ran into at least one homesick WoW escapee with a city named Stormwind. WoW eventually had to combine entire realms (worlds).
Let's not relive that here.