From what I read, Mourning seemed to be nothing but a huge management desaster. Obviously, it isn't released yet - and I doubt it ever will (pics look promosing, though).
Things worth looking at IMHO are Planeshift (
http://www.planeshift.it/ ) and Infinity (
http://www.fl-tw.com/ ). Both are non-commercial and offer possibilities to participate as a developer. Far better than everybody starting his/her own massive OnlineGameProject, I think.
Back on topic:
MMORPG concepts is a
very complex topic, I think. At least, we are talking about generating completely new worlds
This is what just came to my mind:
First of all, I think a MMORPG needs to have a decent and easy interface (as offline games need, too. X2 anyone, hehe?). Wow really is a standard here.
Then, a good prediction system for smooth movement is needed, too. E.g., 2nd Life (
http://secondlife.com/ ) lacks in that, I think.
Another "must" would be players' participation via add-ons. This way, inventions come from the player base, too.
Repetitive quests could be there (sometimes, I like stupid farming in the evening, while thinking about the day, hehe); but it should be an option, not a must.
Impact on environment - as it is done e.g. by AutoAssault (
http://www.autoassault.com/ ) is a first step into the right direction, I think.
Economy... ah, economy. One could write a book about online games' economy models (and surely some did already). Basically, I think, the economy should reflect real-world standards, so that people can easily adapt and accept it. How this could be done in detail? Dunno, really...
my 2cents
"Yessir, I'll be happy to make these unnecessary changes to this irrelevant document." (Dilbert)