- Emphasis on horizontal progression
Some vertical progression is fine, but the game should be based on your ability to use your skills at the right time, rather than being significantly more powerful because of level and/or items.
- World without a player
The virtual world and all it's NPCs/Monster should exist and interact with one another as if the player wasn't even there. The player's impact on the world should always be minimal. Events should be occurring all the time which are optional but reward the player for participation.
- Minimal static questing
NPCs can still provide quests, but they should lead to events. If two teams have the same quest, the team that gets there first and completes it gets the reward.
- Carrot and stick society
Want to kill a peasant? The villages will attack and arrest you. If you break down a door to a house, expect to pay or suffer the consequences. If no one sees or hears you do it, expect to get away with it.
- Destructive and constructive environments
Want to burn a house? Can do. The villages will rebuild it. Want to cut down a tree? No probs, but some dyad will regrow it. Just be careful not to set the forest on fire on your first day ;)
- Death is bad
You don't necessary have to lose your character completely upon death, but the consequence should be enough to piss you off for the next ten minutes.
- Difficulty through strategy
The goblins aren't hard to kill because of their level, they are hard because the sneak up behind you an attack in numbers. Each enemy should have different attack strategies. It's good to feel 'hunted' sometimes.
- Spawning and movement
You should never see someone appear out of no-where. Spawning should happen out of sight of players. Enemies should not be glued to areas, they should move around and perform believable tasks.
Forget aggro bubbles. If something hears or see you, then it reacts accordingly. They might ignore, observe, flee, hide, attack or call for re-enforcements. Also if an enemy is losing the battle, surrender and fleeing is an option.
- Players must be able to feel safe
PvP should be kept to certain areas. This may be an arena or the 'borderlands' etc.
- Convenience vs Immersion
MMOs should appeal to both the casual and hardcore audience, with minimum sacrifice to immersion. Its great to be able to teleport everywhere, but unless 'teleportation' is apart of the story somehow, the game loses a bit of it's immersion. Same goes for bears dropping gold and bastard swords. It's nice to get such drops off wild animals, but it makes no sense what so ever. There needs to be a balance between player convenience and game immersion.
- Realism vs Fun
A truly realistic virtual world, would be no fun. The game need to be a game, but with elements of realism. A good game will have found a balance.
- Solo vs Grouping
The game must cater for both. Grouping should be rewarded to encourage community involvement, but solo players should not be penalized.