From playing WoW in original beta to launch and through so many many many years. I have to say The Burning Crusades was the best time in WoWs history. They had added some quality of life add-ons. Dungeons were hard and needed CC and teamwork. Started the arena for people looking for pvp small scale matches. You had to travel the world and know where places were. There were big groups getting together to kill the world and WOW Classic Gold raid mobs on the server. You had to make friends and be a good person to get into groups or pug into a raid.
Once WotLK came out it was all about getting queuing up for dungeons with random people not on your server who you will never see again and people really started to act like jerks. Plus all the 5 man dungeons became are fests about clearing as fast as you can. That really cut the skill level done in the player base to be good. It was fun till the Call of the Crusader raid came out along with badges for loot that was better or a few item lvls below raid gear. Killed the majority of the guilds that were doing 25man but weren't super huge guilds that competed for world/server firsts.
I played an Undead Shadow Priest and World Of Warcraft Classic Gold mostly a Tank and Fury Warrior. Nobody would let me play my Spriest or Fury warrior because they were seen as inferior specs unless one my buddies tanked or we were running a raid.
I finally quit in Mist of Pandaria because all we were doing was grinding rep and badges for gear and I lost that being in a game with people on the same server feeling. Came back for Legion but that was a crap show that locked you to 1 character and was not fun. Just my two cents thanks. I think Classic is going to have that following of people like me but it is just too late and Activision won't see any reason to keep it running longer.