It is the landmark of MMO's, no MMO before or even after it (yes even the further expansions) managed to capture the magic of vanilla. Some of us (like me) even consider TBC already adding unnecessary changes and additions. People say about unbalanced classes and skills, and this is what made vanilla fun to play. One time you were at a disadvantage but the next time you could feel like a king when the stars aligned, the unpredictability of it, made me coming back and wanting to play more. When everything is balanced and bland like it is now, it is just boring. Todays WoW has lost magic and fun to 'play it safe', which backfired for Blizzard because 'the old players' have left and subscriptions are at all time low.