OPINION:

From the experience I have had in many MMOS I have determined some things as being left out of the necessary whole for role-playing games.

1) A lack of a designer interaction

Successful role-playing games have a sort of interactive dance between the designer and the players, using computers as a medium we call these people groups developer and user. But there is a symbiotic language in communication that is demonstratably missing from the course of action. Simply placing a rejectable narrative into the MMO soup does not offer enough reward for time spent.

2) Strong narrative

Directed play in MMOS, is not a bad thing. In fact often times when given too many options a user will feel confused, and not know what to do. Coddling playtime as well as achievements do not remedy this problem, but allow players to experience the consequences of their actions
through well designed narrative does.

3) Complexity

There is a distinct lack of game complexity in MMOs across the board, that has been largely commercially constructed and more recently through use of game metrics. Most often we look at these as combat systems, crafting systems ect. But these do not satisfy whne you want to climb a rope, jump through a mirror, float under a door as a gaseous form ect. These sorts of ideas that are all non-combat in nature are relegated to the back row as "niche" market. But this niche market is the grass roots of what roleplaying is today, and it is these experiences that are missing. Slaying the dragon is all very well the highlight of the show, but without "a greater comprehension" you could never demonstrate Alladin's lamp, or Jack and the Beanstalk ect. IT's these stories in their fullness that make adventuring truly memorable.

4) Material logic

While Bethesda stands head and shoulders above the rest in this area, I worry that traps, pits, puzzles, body dragging ect will be cut from the list of importance. Doing this will be the death of your MMO, as taking out the essential parts of Kotor was for Swtor.

5) Heroism and Mass Media

Cookie cutter fetch quests, fill in the blank ect. are a scourge of online gaming. They "command" achievement above all else. This is not only a problem of realism but a problem of people. This ruins the effect of the heroes journey and exploration, and puts them most subject to the mass of players that think gaming online is all about the "bling". IT's not just emergence of player behavior, it is the crass and crude reality of teenage angst, twenty-something perfectionism and 30 something wobbly know-it-all isms.

A strong narrative that is IMPERATIVE to good roleplay needs not only good search tools but protection from this consumption-based fervor.
You MUST protect your players, not just from greifing, but from enevitable detraction of the your game.

6) Realism kills Narrative

People play games for different reasons. But if you want to keep the essence of your game, you must apply even greater abstraction (especially to combat and it's emphasis). For 2 simple reasons
1~ The uncanny valley, the more something becomes real the more we tend to judge it's faults in comparison. (distraction)
2~ It creates imbalance, this isn't a player vs. player problem. But a problem of importance, where you cannot emphasize the story because you are too busy "acting".