WoW Vanilla/Classic is a true mmoRPG.
Just like in Morrowind, Dark Souls, Dragon Quest...you can just be wandering around playing at your own pace, exploring, visiting etc...
The RPG aspect is in a terrible shape in retail right now.
Never got the chance to play Vanilla but I still have the strategy guide from the Battle Chest reading lines like that made me fall in love with the game even before playing.
Sadly in today's WoW the concept that you can "play as you wish" and have fun is lost, but I really hope to find people with this mentality when Classic will release!