Many great games are ruined by a lack of a community feeling. If there is no community, its not an MMORPG its just an RPG, I think that the game should force a community feeling, and interaction with other players.
I hear a lot of complaints about Sword of the New World lacking community (partially because of the bot system they came up with) and these complaints drive people away from the game, and ruin its reputation
Things that I have seen in games that help build community:
Virtue Points - Conquer Online
Encourages high level players to interact and help lowbies
Team Experience - Air Rivals (Space Cowboy/Flysis/Ace Online)
Team members received 30% more exp for a full team
Friend Experience - Air Rivals (Space Cowboy/Flysis/Ace Online)
You received 0.5% more exp for each friend that was online (30% exp maximum)
Team based quests- Cannot remember
Team based quests build a reliance on other players and can help create new friends
Guild Battles - Metin2 (did not get far enough to do this though)
Creates a fun PvP environment and builds a sense of loyalty to your guild
I played Conquer Online on and off for over 5 years, and I believe one of the big reasons I kept going back was the great community on my server, I made a lot of friends and was always sad to see someone quit.
-edit- I think the bot system is a great idea, and it helps even the playing field because creating and downloading a bot is pointless because you provide one.