Just my 2 cents, but MMORPG's done correctly would attract all walks of life.  I have yet to see a MMO actually be able to satisfy the hunger for all types of gamers.  There are those who like to pit their own strength against other players in PvP type battles, those who are more PvE oriented, and those who like the social life that MMO brings. 

Ive played SWG and EQII, and yes, played GW as well.  I have to say, if someone could morph all these games together in the D&D world, I would be flabergasted and in awe.  The community features of SWG, the crafting, the trading, the player cities, the vass amounts of transportation available .. SWG is a truely wonderful game for the die hard SWG fan and the gamers who appritiate the social life in MMO's.  But I will admit the quests and missions of EQII and Guild Wars beats SWG out of the water hands down. 

The whole time i was playing SWG i just kept saying to myself, "if only they had a better quest system".  there were some of the non combat profs that were completely igonored when it came to quests, and the mission terminals were ridiculously repetitive. 

I loved the way that the quests and missions were set up in EQII and GW, but i hated the limits they put on the customization of your character.  Your "toon" is who you present yourself as in the MMO world you choose.  And for the diversity that SWG put into their characters and the economy, NO game has yet to match them in this, which is one reason that the game was so fun.  There were no "twins" and if you saw someone who looked too much like you, you could always go change your outfit or your hair color, or your skin color, or a number of other things that the Image Designers in the game were able to help you with. 

The crafting professions in SWG were vast and not so tedious as those of EQII ... yes, it may have been TOO easy, but their has to be a happy medium between it being too easy, and so freaking mundane you want to shoot yourself for attempting to make one item.  EQII crafting system sucked hard core. 

I know this isnt really a "add it to" type post, but maybe by voicing the likes and dislikes i have with other games you all can find a way to draw in all those like myself who want it all.   a game that can offer me the choice of fighting or merchanting or whatever i want to do. 

I believe the key to a great mmo is to have an awesome economy and NonCombat Profession system available along side the great Combat and PvP that most mmo's concentrate on.