So say, if I choose to put food into the game, it will make a soft limit, in the way that you have to use time (building farms) to generate more food for your warriors? And then having the price for farms go up as you level them up, it would cost more and more to keep a bigger army.
But, because it's an online rts it also takes more and more of the players time the bigger his army and empire grow, so that is a kind og soft limit as well you could say?

This is the hardest thing to do with feedback loops: Identify the loop.



What you have done is seen Farms -> Food -> Soldiers. As soldiers need food and farms produce food then the more soldiers there are the less food their is (but, as the soldiers don't produce food, there is no loop).

However, this is not a loop. This is just a linear system. The loop is the Farms -> Food -> Farmers -> Farms loop.

Farms -> Food -> Farmers -> Farms is a positive feedback loop.

The more farms you have the more population you can have and the more farmers you can have.

So building farms feedback into having more farms. However, anything you build that uses food and is not a farmer reduces the rate this feedback loop operates, but it doesn't eliminate it (or turn it into a negative feedback).

Time is a bad resource to try and suppress. This is because each time you do this, you are dictating what a player has to do. You are taking away from the player the ability to make decisions. For a player to develop a strategy or choose tactics, they need to be able to make decisions. This is an essential part if you want the player to be able to develop their own strategy rather than just implement your strategy.

HEre is a suggested feedback loop:

Population Needs houses. Houses take space. Population needs Food. Food is produced on Farms. Farms take up space.

The loop is: Population -> Space -> Food -> Population

So, increase the food and you can have more population, but with the increase in population you need more houses and that takes up space, this leaves less space for more food production.

If other buildings then take up space, this makes the resource of "space" the limiting factor in population size.

However, if you allow the player to gain space from conquering other players, then this creates a new positive feedback loop: Victory -> Space -> Food -> Soldiers -> Victory.

The more victories you have the more space you have and thus you end up with a larger army and this makes it easier for you to have more victories and get more space. End result = Positive Feedback.