I can tell you, leveling BLU in FFXI was one of the things that really got me antiquated with EVERY zone and EVERY dungeon pretty well.

I really hate an excessive amount of instances because it completely detracts from what this genre is, a Massively Multiplayer Online game, not just a Multiplayer Online game with towns acting as lobbies. If you want multiplayer dungeon running with some friends, play Diablo or Guild Wars 1. The majority of the world should be there for everyone to explore, at any time.

"Oh hello, what are you doing in Gustav Tunnel? /wave" is preferable to "Oh so you're waiting for a party outside of Mun-tuy Cellars too, huh?"

Instanced dungeons have their place, with time limits, traps to spring, levels to pull, minibosses to kill, challenges to overcome, and loot to reflect the difficulty of your victory, but when everything is instanced, it may as well not even be called an MMO.