Whatever makes the game fun to play. I think it is ridiculous when designers complain that people aren't playing the way the game is designed. Game players will find fun in a ball of yarn if that is all you give them, but by no means get upset when they use that yarn in a way you didn't expect. That doesn't matter to me. In my game, Atriarch , the characters are persistent which means the character stays online even when the player is not.
Many games suffer from troubled economies.
Over time money is consistently devalued to the point where it becomes useless in player-player trading. Player-created items are the best items in the game. Program better so as to eliminate duping bugs. In Atriarch , we are a true physics based engine, so everything has physical properties, for example, mass. So basically, you can pick up pretty much anything and use it as a weapon.