Patents should be incorporated, with a facility for patent trolls. Or to put it another way, there should be a possibility that when you buy something your ownershipcan be disputed, either immediately or later.

The banker should also be a player in the game as a role unto itself, not just as a passive bookeeper, but rather someone who makes money off being the banker. This of course then requires the possibility of multiple competing bankers.

And lastly, there must be some sort of speculative market, such as commodities futures. Ones which can be affecdted by random events such as hurricanes, drought, or revolutions.

Paper money, or some way for one player to think they have an idea of how much money each other player has.

Gary