This is a concept idea from me regarding the designs of various civilizations in the game. Some Civs in Aoe4 will be more or less like Aoe2 and some will be radically different. That’s why I am sharing my ideas on how that can be done.
There are three civilization criteria that I thought of.
FEUDAL FACTIONS
This is the standard form of civs. English, France, etc can fall under this criteria. They are pretty much like Aoe2 civs with a special bonus power.
Special power: Feudal Levies
This power allows them to turn their peasants (villagers) into various trash units like Spearmen, archers, skirmishers by sending their peasants into military building to train. They can also train trash units from military buildings and later have them relinquish their weapons to turn them into peasants. At any moment player can send these trained peasants into the town center to turn back into soldiers. They only cost resources one time when they are trained. Basically, this power allows feudal civs to have a powerful peasant/cheap army to throw at their enemies and later use it for economy during peace time.
Taxation: Fedual civs can at various interval tax their peasants to get some gold. This will lower their productivity for a period of time but grant a good amount of gold instatnly. Various research modifies this skill.
Mercenary: Feudal civs can hire a limited amount of mercenary units from mercenary lodge by spending gold. The variation of mercenary depends on the scenario map and campaign. Also you can only have a short amount of mercenary troops. Also mercenaries don’t fall under your population limit.
IMPERIAL FACTIONS
Civs like Byzantium, Chinese can fall under this. They have two population; one is for civilians another is for military.
Special Power: Imperial Decree
At different interval player can initiate an imperial decree (or they can spend resources to initiate it whenever they want). Through these decrees player can change the percentage of population distribution between civilians and military. So at later stage they can allow military to consist of fifty percent of their population if necessary. Their trash units are stronger than other civs but cost little bit of gold. Through decree they can also change focus from certain units to other, allowing faster training rate of one particular military buildings. Basically, Imperial Civs have slightly smaller but more of an elite army.
Taxation: Imperial civs always get a small steady income of gold from their number of active peasants. Through Imperial decree they can increase taxation rate by lowering other production rate.
Mercenary: They have access to huge variety of mercenary and can use other resources to buy them (after certain research or imperial decree). Faction like Byzantium can have Varangian mercenaries.
NOMAD FACTIONS:
Mongols and other steppe faction will fall under this. They’ll be the most unique.
Special Power: Horde
Instead of peasants they get clansmen which they can turn into nearly all form of military units (Except powerful castle ones and siege) quite similar to feudal levies. Later they can turn their military units (even those created from normal military buildings) into clansmen for economic production. They get gold and other resources by destroying enemy buildings and after some research can even capture certain enemy buildings by nearly destroying them. They can in certain cases capture enemy peasants (like one out of five) which they can use for production (unlike clansmen these peasants can’t turn into military units). They can only capture them if the enemy faction doesn’t have any building nearby (meaning they can capture them after destroying the enemy towns).
Nomad civs don’t have access to certain “artisan buildings” (which can create gold for you) and have limited defensive buildings. They can however set up some of their building as “permanent” or as “movable”. Movable buildings can be easily relocated but they have smaller hitpoints.
Taxation: Don’t have that feature instead loots enemy buildings.
Mercenary: Can’t hire them however can steal a limited amount of tech by destroying enemy buildings.
There are other faction criteria such as Merchant Republic and Tribal however for the base game these should do. Let me know what you guys think of this. Share your ideas on how to better them.