My idea for a game is an evolving MMORPG.
Where many things are taken into account in regards to your charcter.
Also the world evolves around you, even if you arent there to witness it.
some examples include:
A birth and death rate for towns and cities. The shop keeper died, so that particular shop closed down / has a different owner. A group of 18 year olds join the local guards, the city now has more guards protecting it. An expansion rate of say one person every 3 hours, then when the city town has +random amount of people they might go off and start a battle somewhere, or migrate somewhere and set up a new town. Same for both sides of the game. If the two factions have a "roaming" population that comes into a certain range of each other they more then likely will engage in battle.
With quests you are given a time and lets say you finish them late continuously, you earn a reputation as being a bit unreliable and people will be a bit reluctent to give you quests that meet a deadline.
Actions such as getting caught commiting crimes against your own people earn you a bad reputation too.
You can go to the library and read books and be able to answer intellectual questions from people like wizards, which might result in a quest or two. Or at least someone who might enchant that weapon for you, depending on your reputation.
You can work in the smithy and gain a bit of Str and Stam, as well as learn to craft some items ( mini games ). Work in the farmers field, gain a bit of Str and Stam and gain some knowledge about crop growing. So you tend your own field ( after earning / buying the land ) to make a bit of cash. Worker for the local builder, gain some stats, some knowledge of how to build your own place. Basically any form of employment to earn a bit of gold, a few stat increases ( when done for a few weeks ) and gain basic knowledge increases to the task at hand ( which also allows you to earn more money doing that task ). Can also join the local guards in towns and cities. The thing with my MMO is when you log out, your guy becomes an NPC until you log back in, so you can some cash while logged out. Your character can still be killed, but drops no loot, and doesnt loose any items. Your character does his assigned task until you log back in to cancel it. So in the event of an enemy faction attack on your town and you are a guard, the computer can use your guy like any other. Obviously the better geared / higher level it is, the better it will perform and the more likely the attackers will be repulsed (sp.). Any dead Characters / NPCs will be respawned as part of the city growth rate, before any new members are added.
So your character has the basic stats of Strength Stamina and the such, but also has secondary stats like Temper, Attitude, Kindness, Efficiency(timewise) which are scaled on a sliding scale. So in conversation with an NPC you choose angry hostile responses your Temper( more Temper / more angry) goes up, and perhaps loose a bit of attitude as well ( negative atitude ) and your kindness might go down depending on how agressive the choices you took were. Based on these "personality" stats your chat options to NPCs will change to reflect those personality traits that stick out. There will always be one option that goes against your current personality, just incase you ever want to attempt to remedy your current personality.
Some people want a homocidal manic questing for them on a particularly gruesome task, where others will bolt back inside as soon as look at your character. Some want the gentle kind hearted soul to help their sick dying child, even if the child cant be saved, maybe a kind comforting word at the end.
I want to stick to the 2 playable factions, but also have an ultimate evil NPC faction, something akin to the Liche King character in WoW, that cant be reasoned with.
His base of opperations is like the player factions, in that his army grows and raids the player cities and sets up other towns, just like the player factions. Except his lot grows faster and has a more of a tendency to seek out player towns and cities to burn them to the ground.
In effeort to make it feasible for a small group of players to take out his advancing army ( again using the LK character as reference) you can enter a flying Ziggerout as a dungeon after killing one of his army generals for the portal key. Then you run the dungeon, working you way to the control node, destroying the (LK's) control over the advancing army which then crumbles to dust ( mostly looking at an undead third party here )
Players from opposing factions CAN work together, or they can arbitarily destroy each other. Including taking the fight to the undead 3rd party. As well as dungeon runs.
Thats my ultimate Game, i dunno about an MMO setting, but has to be a multiplayer setting at the least.