Swamping so many armies in a single game for the sake of it sometimes are just getting pointless.
The "exotic" armies (from European/US POV) are there to enable to simulate a "local" conflict, not to pit the military might of Cambodia against the US. Also, the points cost of a single Abrams allows you to probably buy a company of 90mm armed tanks, ensuring that some of them survive to make penetrating side or rear shots.
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Balancing is one thing that kills realism.
It might be important for the gameplay, but it is "meh" to people who loved simulation.
IMO, WW2 German Tanks are incredibly to most of its counterparts, but their maintenance is a bitch so we heard... then it is fine for realism sake to increase the cost of each German Tanks in game, not powering up Russian/American tanks for example.
In most strategy games, airplanes are incredibly cheap and vulnerable, their presence is rather miniscule and mostly serve as mere eye candy. One of few games that I've seen that portrays the effect of air force correctly is Cold War Crisis mod for C&C Generals:Zero Hour. The planes cost three-four times as expensive than the tanks, however their presence is quite decisive in the battle.