You do not want to sell a game engine or a do it yourself video game, you want to sell a real video game. Modding should not be used to create a game that does not exist, it should be used to extend the life on the game by adding alternate ways to play. So you need to have a solid working game right at the start. The common gamer will not play mods until he fully understand and enjoy the base game. The average gamer does not want to tweak the game before playing, he wants to buy, install and play now. When the base game has offered him enough challenges, then he is going to look out for mods.
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Many people suggested raising the maintenance cost for larger empire. I do not totally agree with that
- First, you do not want to prevent players from making larger empire, you want to make sure other players can stay competitive. If empire cannot grow any more, there will be no military domination victory unless you stop the game when a player owns 2/3 of the map.
- Second, calculating maintenance is annoying and should be done by itself. I promote the idea that each city should be able to maintain itself. I really liked civ rev that had no negative value to calculate.
City production could be calculated this way: Income - maintenance = Net income.
What the players really cares is the net income that will go into the treasury. So if you could abstract the maintenance and only show the player the net income, that would be easier for the player to manage. Net income would be used to maintain stuff outside the cities, like mobile armies, or go in the treasury which could be used for various purpose.
One of the way to abstract maintenance could be that the size of the city ( in population) determines the amount of buildings or units a city can maintain. This abstract all the tax collected by the population and the required population to operate the buildings as : this city can hold a maximum of 5 buildings right now. This way, players does not need to bother about the accounting of each city. It prevent also players to have a city in deficit (too much buildings for it's size) which would be supported by the net income of other cities.
Players, for example, could decide to build 2 barrack to gain more unit production. This is where it will become more strategic to determine which building you want to build according to your objectives. I might cost you gold to place new buildings so that changing your buildings configuration many times will empty your treasury.
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As for constant progression, there are many board games that use a system like this since it is harder to level production relative to empire size. For example, in Endeavor, each player take a buildings every turn, at the end of the game, all players will have too 7 buildings. So the growth is constant. In starcraft the board game, you are limited to 4 actions per turn. So if you have a larger empire, you will have less actions to manage your empire and will only bother about your borders. So it makes you more vulnerable to a player that will use his 4 actions against the same planet.
Personally I think making Tech and Magic research constant should be the solution. Also considering that there are so many research path, even if players all have the same research level, each player will still have a different combination. People suggested that heroes, quests and events could probably boost research. I totally agree with that since it is not related to the empire size.
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Therefore, how should resources be handled in the game.I find it a bit stupid that you need a gold mine to get gold income. It makes the game look like in warcraft where there is no ecomony, all the gold spent goes into another dimensions. Here are some suggestions on how the resources could be managed according to various priorities.
Flat bonus: The city will gain a bonus to a stat if it controls the resource. Like in MOM, Game gave you +3 food, gold +5 gold, etc.
Exponential Bonus: The more you control of the same type of resource, the more income you gain. (ex: 1 gold = +5 gold, 2 gold = +15 gold ) This income should be empire wide. The advantages is that it is easier to lower the income of your ennemy by capturing cities with resources in order to de-multiply their bonus. Still, in order for the resource multiplication to be logical, you need to have very good communication between your cities which might not always be the case in medieval times.
Lock and unlock things: Having access to certain resources unlocks you the possibility to build certain buildings and units, So capturing these resource will weaken the enemy empire. Players can trade their access to resource in order to diversify their resources.
Cumulative with Production cost: Same as above instead that each turn, you accumulate a quantity of each of these resources and building stuff deplete them. So If your resource gets captured, you can still benefit from a reserve you could have accumulated. But if there are many resources, it is annoying to keep track of the amount of ressource of each type you have. So I prefer Lock/unlock method.
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I don't see anything else to say right now to say. If people need help to design an economic system, I don't mind helping as long as people state what they want and do not want to see in the game.
Personally, I prefer something relatively simple with little calculations so that the players could focus on important decisions to make rather than how to reduce my gold deficit.
