Give the North Koreans the military wonders in the begining like Sun Tzu's and Magellen's and stuff and then after they lose their momentum have them become obsolete.
Specific ideas?
North Korea
Sun Tzus - Obvious...
Magellen's - Could give midget subs a surprise advantage they'd enjoy in wartime.
Lighthouse - Those small coastal boats could journey out, but as the war goes on they lose their ability to be maintained. This could be used with all ships by toggling the Trireme flag. Actually...it coudl be triggered by time or by an Alled occupation of one of the NK ports.
Great Wall - Will prevent the allies from making an assault right up the peninsula. That can become obsolete after they make an amphib. assault farther up near Seoul.
Colossus & Adam Smith's- Used to simulate the demise of the North Korean economy after Bombers take out factories and things. Actually, you could use that technique that Shay used in his Sacraficial Blood scen, where you could make Factories in NK so the ROK doesn't know which will trigger the loss of technology (and subsequently wonders).
Hope you weren't asking for actual names of wonders.
