I was a beta tester of EQ1, played for a long time through various characters including a halfling druid and a human monk. EQ was great in that is was the first real 3D MMO I had played and the scope of the world was amazing. You would travel from places like Freeport out to Qeynos and just the run over would be an experiance, finding a random dungeon that no one told me about, or that time I accidently wandered into Mistmoore. When I started WoW I even named my first pet, a crocalisk, after the famous EQ crocodile, Lockjaw.
Really, the issue is that over time that massive world loses it's magic. I have a similar feeling with WoW all the time. I remember when walking into Stormwind as a little human rogue during phase 2 beta blew my mind, the huge statues, the way the music starts up in a chorus, and finally entering the city with the keep looming in the background. After a few weeks though? It just became that place that was not Ironforge, and even Ironforge just became that place with the AH.
Wonder comes from seeing things we never saw before, but over time, those things become old and familiar, and a lot of the magic gets lost in them. I found myself quitting EQ1 not because the game lacked expansive and interesting locations, they still had some charm, but because those things that started out as wonderful (the long trips, the long boat rides, the huge cities) over time became tedious, familiar, and after awhile, boring to me. They were unable to grab me back with the expansions.
Now I play WoW, and every time I consider quitting that game, they remove something that was annoying me and suck me right back. Crafty little bastards.