I realized I hadn't come up with a new game design since before I played Skyrim, so I wanted to work up a concept incorporating what I learned from that game as well as my frustrations with it, as well as other games I've played since then, and especially game types I've wanted to play but failed to find any of.
I think the best thing about Skyrim, Fable, and this world-simulator genre is the fact that the player's actions shape the world. The power of this can be shown by contrast; the most frustrating parts of Skyrim's design for me were those where I ran into a part of the world that was not shapeable by the player, or which undid the player's actions after a day or two. >.< On the other hand, IMO the best thing about the MMO genre is the feeling of being in the same living world with other players, and getting to see the results of their efforts within the game (their mounts, gear, buildings, collections) because these help the player find goals and compare their achievements against others. So I'd really like to come up with a game design that has both of these great qualities, but they kind of seem to fight each other. When should other players be invited in for social value, and when should they be kept out so they don't muck up your own projects and territory? Can shared and personally instanced game locations be effectively combined in an MMO?
Guild Wars 1 is one example of a game that attempted (and IMO failed) to combine these things). It was highly recommended to me but when I tried it I didn't like it at all. I only played it for 2 days before deciding I just didn't like it at all, so if I say something incomplete or wrong how the game worked, that's probably why. Bat as far as I can remember, that system basically had shared cities and solo wilderness (unless you invited another player to enter with you). This didn't work for me at all; I never got to see other players doing their own thing in parallel to me, which I think is essential to making a world feel real.
A Tale In The Desert had almost an opposite system - the wilderness was shared, and there were no cities or other population centers to encourage interaction with other people. The shared wilderness was the worst of both feelings; desolate and too big, yet messed up by pollution and decayed buildings left by previous players. Despite being an MMO, much of my play time felt the same as that of the single-player game Spore, or Creatures Docking Station - depressingly empty of any socialization except the occasional sight of an artifact left over from another player you'd never actually meet.
The third example I have been thinking about is Wizard 101. The shared part of that game was pretty successful, except for a few problems with some areas having too few players and some having too many, which is a difficult pacing and balancing issue for any MMO. The ability of players to join an existing fight was great (this feature was nice in Dofus too). The blending of "what's a monster to be fought" vs. "what's an NPC to be talked to" made the world feel populated even when no other players were present, much like Skyrim does. Most dungeons could be run successfully by a single player (yay!) or a full party of 4. The personal/dorm room area was a good private space for decorating and sim-activities such as growing plants. There were a few downsides though: the player could make very little impact on any shared area other than killing a boss which would soon respawn. It was possible to visit another player's private area, but there was nothing to do there so it wasn't fun and there was almost no reason to do it. Players rarely commented to each other about their accomplishments in these private areas, and it was easy for these areas to feel finished or futile even to the player they belonged to. The crafting system, being 2/3 about these private areas, also fell under this shadow of feeling futile. But, that game overall had a big focus on not giving players opportunities to harass each other because it was supposed to be child friendly, so they intentionally created barriers to a lot of potential interactive gameplay.
The fourth and final example I want to look at is the kind of MMO which has a lot of player-created content, including the ability for players to create levels with localized gameplay for other players to explore. (Second Life?) I've never actually played one of these games. (*whacks self with a newspaper* Bad game designer! No twinkie!) From what I've heard their main issue is in directing the player to good content in a logical order and at a good pace, maintaining some kind of balanced economy of effort and reward for player-created content, and filtering out spam and trash.
Okay, that's everything that's been swirling around in my head. What do you all think? Is there an ideal way to balance the ability to affect (your version) of the world and have it react in a way that customizes it to you, the ability to not have your stuff screwed with by other players or constantly reset to default by the game, and the ability for people to regularly encounter each others' personal projects and be encouraged to discuss and compare? Have any additional comments on one of these examples, or a different example of shared stuff vs. private stuff in an MMO?