So, we have wood, food, stone, and gold. But thats a very simple economy.
For example, leather armor uses tanned leathers. Ships need specific types of stored food (barrels of salted pork come to mind) And lets not forget iron is used for weapons.
So what about an economy that produces the second tier resources, and then allows for the creation of troops? For example, a blacksmith could allow for the production of weapons from iron. A smelting refinery could allow for iron from stone production. And a quarry could allow for small continuous stone production for inputting workers (who get killed in the quarry thanks to accidents)
Other things like barrels of food (wood + iron + food) could be required by carracks to make.
And mounted knights need armor, which could be produced in blacksmiths in the imperial age. This is continuous production, so if you want to knight spam, you need more blacksmiths to outfit them all.
With an entire economic chain, we could see the game have a massive slow down in terms of rushing, and instead be a more idyllic relaxed game where people build massive sprawling empires, and where combat is saved for when the various empires are fully built. It would be far far more epic then.
As an alternative game mode or a mod perhaps, but for normal games I don’t think many people here would like that idea, as there has been plenty discussion on making games more fast paced rather than longer.