I was thinking about the entire population as soldiers question that has come up on these forums and I thought of a system that could add some dynamics to the game. I'm not sure whether such an idea has been voiced, but I was thinking of a "Standing Army" concept that would allow the player to determine what percentage of his population should be soldiers.
If you take the current behavior of the game (everybody fights), that could be set to some arbitrary value like a 70% standing army. If the user chooses to reduce the percentage, then he can experience bonus economic benefits but at the risk of being unprepared for an invasion or being incapable of mustering an invading force. If the user chooses to increase the percentage, then he experiences economic penalties but soldiering bonuses and the benefit of having more people available to fight.
The user can change the slider at will, but it takes time to scale either way and the economic bonuses are lost immediately. In that way, changing directly before an invasion would in fact be costly and of no benefit.
