This is the second post in the series responding to Azariel's questions, defining my view on role-playing in MMO's and in games in general. First one dealt with definitions, this on my thoughts about roleplaying in games.
The most memorable gaming experiences, both in pen and paper and in computer games, for me have been the ones I can only describe as total immersion to the game. Taking up the story so personally that you really take the place of the avatar/character on screen. This comes up from several factors, but for me the most important is that I'm interacting with the world as the character, not as the player through the character. Thus there should be better tools to interact with the world in character rather than using the game as a social interface tool.
Chance of making change
Another important issue is the possibility of the single character to make difference in the world. It's the small things that make it, like scribbling your signature on the toilet wall... not that I'm encouraging it in real, but the tangible 'mark' you/your character makes to the world. In MMO's currently the issue is relevant because of the fact that the NPC you have to kill will spawn back in few minutes only to be killed again later by another player, the quest giver will be handing out the same bundle of notes to be delivered right after you have acquired yours and so on.
If the character kill a boss or a quest mob, this mob should be done with: no more encounter, and rest of the game should reflect that.
Which leads to the next one.
Character impact in the world
The standard heroic high fantasy story tells about the stable boy who gets to be the hero saving the world. Naturally the sandbox world would make this harder to acquire, as the stories would rely so much more on the shoulders of the character interactions and the world. However, in a story and quest driven surroundings of EQ2 and WoW, the main storyline, even though coming together from several quests, should be possible and even encouraged. I myself have gotten frustrated over the lost questlines in WoW, namely the Sillithids (the 'chapters' are spread across and without a growing storyline), Burning Hand (the storyline dies too soon, just when the starting Horde character starts to get interested) and so on.
The stories could come up with a story for the character, where this characters actions really make the difference, have an impact in the world as whole. It doesn't matter if this is just an illusion, but it would be very real and personal experience for the player. In WoW the new Phasing technology seems to be capable of creating the illusion that your character is making the difference: My bet is that this will be the main focus of the Blizzards secret MMO project.
All actions have consequences
In the real world you can be an asshole, but the world will treat you like one, too. If you steal, you'll be facing the consequences. Why on earth isn't this viable in the fantasy world? In WoW you are encouraged to kill NPC's not following the consensus, you are asked to steal and murder without any consequences.
However, in single player games like Fable2 and Oblivion your every decision effects the way NPC's tied to certain factions interact with you. Cheat one, and the others will not trust you. Kill someone, and you'll have the guards chasing you. How hard could this be to implement in a MMO? Darkfall has something along the lines, though if the scale goes from -100 to +100 as Syncaine reported, it makes is possible that you kill baddies till you are at +100 and then some of your own without any consequences as far as you don't drop below 0.
Tools of the trade
The current MMO's are more like social playgrounds for the gamers instead of the worlds in which the characters live: the tools of interaction are very limited at best and the game aspect is way too profound. However, you cannot win a MMO, as there are no real winning conditions.
Like I have earlier stated, the social tools should be upgraded. In role-playing side the upgrade should be made so that the interface itself reflects the in character and out of character interactions, making the player-to-player interactions more character-to-character based, and thus creating more immersive surroundings.
If you think of WoW, the role-playing tools are very inadequate and to really role-play your character you have to work the system around to make it work. Instead, IMO it should be the other way around: to be able to interact only out of character should be the harder part.
Even the earlier single player games have had the technology to make each playing of a game different through the effect of what you as a player decided to do. The persistent world however breaks this illusion by forcing the same experience to every player, regardless of the decisions they make.
I'm not saying that these things are viable for execution with the current technology, but they could be worked towards the end of total immersion.
The reward should be satisfying, immersive experience, in which the decisions you make as a character make the difference in the world. And in the story of the character.