This is wrong, TBC ended at 11mil because thats when heavy advertisement really started, i remember WoW banners EVERYWHERE, LITERALLY along with free gear from the Season 1--->Season 2 fuck up and then Wotlk barely added 1 million, its where the actual decline started happening because ICC lasted to long and even the casuals caught up and the whole "EVERYONE GETS TO RAID, DIFFERENT DIFFICULTIES GUYS" started.
Then Catacylsm upped the difficulty for the masses when they were used to facerolling stuff and they didnt like it.
When it comes to Vanilla WoW vs Now?
Only difference is: RPG vs ARPG
WoW used to go by RPG standards, not caring about balance, just acting like the usual RPG rules, resistances, so on, so on, long questlines etc.
It evolved past that, people need to understand that, there is no RPG element left apart from leveling, and its an Action RPG game pretty much.
Its exactly the same game in its core though, exactly the same game, Max level-->dungeons-->Raid-->Wait for next.
As someone that was there in Vanilla, in pretty much BiS gear or close to BiS from Naxx/AQ40 i can tell you for a fact, Vanilla was a pile of trash compared to today WoW, it just had the RPG element, that is all.
Unless you consider it fun, running around in so much gear that anyone that doesnt have same gear as me or isnt a tank i can 2 shot with my white attacks, not even discussing abilities, yeah it was fun when i was 18-19 and you know, having the feeling of "BOW DOWN PEASANTS", now that i am near 30, i simply cant pretend Vanilla WoW was good
.
Good for 2005-2007? Yes.
Good as "New cool thing and RPG element?" Yes.
Good as anything after 2010? Hell no, evolve people.