The problem - maybe I'm missing the point a bit here, but this is my view - with MMOs are the fact that they miss one vital element of RPGs, and that is roleplay. It's not really the game's fault entirely, you have to blame the players as well.
In your standard single-player RPG you have a plot to follow, a storyline to play through, and your choices and interactions with NPC's pretty much dictate how the rest of the world is going to respond to you down the line (think the whole good vs evil choice mechanics they built into Mass Effect and KOTOR and so on). So you're building your character as a part of that world.
The problem is, in MMOs, you're interacting with real live players, teaming up with them, chatting - in many cases these days using services like Ventrilo, TS etc - but nobody actually
roleplays. Everybody is focused on leveling, getting the best gear, killing the opposing race/faction as much as possible and telling Chuck Norris jokes.
So, from my point of view, Slipperyduck has something of the right of it.
After all, RP loses a bit of of its essence when you have standing in front of you the hottest female character in existence while what sounds like the voice of satan is swearing in your headphones because the char just got ganked
