Hey guys, you forgot one but IMPORTANT thing!
In modern life there are no warriors and archers in armed forces of any country.
Any country, even "thoroughly inferior", can have machine-gun equipped arms in 20th century. Say, the US in Vietnam (or, Russians in Afghanistan) fought not vs. longbowmen or War Elephants or Camel Archers - the units on the "savage" side were almost on the same scale as on the "enlightened" side: rifles, kalashnikovs, grenade launchers, portable SAM missile launchers etc.
Some historician (hm, don't remember who) called our century the "posthistorical" time. Savage tribes in Africa watch TV in their huts, every country in the world has railroads, supermarkets and internet.
I am positive that such feature as "leakage of technologies" MUST be implemented into a game!
Thus, we can get rid of those ludicrous situations of mech.infantries fighting against horse archers. We can preserve the balance, by reviewing the barracks system in the game. My idea is to make barracks gradeable and upgradeable...=)
e.g. barracks for ancient melee units
barracks for archery units (costs some more)
barracks for gunpowder units (costs twice more)
barracks for modern units (costs six times more)
You can build modern units in a city without appropriate barracks, but at a higher expence, and units appear without initial experience. And vice versa, building modern barracks seriously reduces production times for units, allows multiple upgrades for them.
Let me dream even further...
I want units to be built in barracks, not influencing city's building construction activities. E.g., in my Moscow city, my "Air Force barracks" builds stealth bomber, my "Infantry barracks" builds a Mech.inf. unit, and at the same time my city is constructing a hospital.
Ahh, dreams, dreams...