I've just realized something. Almost every RPG I've ever loved, I never played by myself. Even single-player.
The first time I "played" Final Fantasy 7, I was actually watching it with 3 other friends, all huddled around the tv together, while one friend played and the rest of us watched and even read aloud the lines of different characters.
Most RPG's I've played in the last 6 years have been played while my wife was watching, or at least sitting by me. Some she even participated, but lately she folds laundry or something and watches.
We will all remember Secret of Mana, that classic which actually focused and thrived on its being a 3-player adventure. I think the 3-player formula works wonderfully. And nothing beats sitting in a room together.
Last Saturday I got together with 2 other guys at one of their homes and I watched a friend play Parasite Eve (PS1) for 2 hours. Why was that so fun? I realized I never could have sat through that game on my own, but we had a blast.
I got into MMO's for one big reason...it's very difficult to meet at friends' homes any more, since I generally put my son to bed every night and I wouldn't want to leave my wife alone any evening when I already spend so much time working out of the house. So it fills that friends gap. Still, if there were a way to make the experience even more like sitting around with your buddies in an MMO, I'd welcome it. A co-op game like Secret of Mana playable online would be great. In fact, I don't think any offline games have come close to that 3-player co-op experience since.