I like the idea, as I was a Korea enthusiast in AW3 and AW1, but if it ever gets done it needs to get done right. Use WW1 as an example of what not to do, that is, release something that doesn't have strategy or goals. If korea ever got added I would like to see:
Two different countries US/Soviets
Soviets with Mig15 and accompanying prop planes such at Yak9u and La7. (Maybe even tamper with fuel settings for them to make them more useful
US with F86's and accompanying propeller planes (F4us, jugs, and 51s perhaps?)
Most importantly though would be to set up a mini war, since we can probably assume Korea will field maybe around 50 players/night on average if it is done right.
So, tanks, goons, and bombers would be necessary for each side. I would argue that you enable all of these for each country. So soviets can fly B29's and drive tigers and m4s. Sacrifice some realism for a balanced arena. So, the basic differences between the two sides would simply be the jets and the supporting prop aircraft. I think that would be good enough. Have the war work just like LW, except maybe some different capture percentages. Maybe you need to capture all but the remaining 2 uncapturable bases on the opposing side to win the war. Maybe have 3 korea maps that cycle through as wars are won. Would also be nice to see a Arena War Tally Tracker to see who is winning over time, Soviets or Americans for bragging rights.
Get a bunch of this stuff set up and going and you will have a bad bellybutton arena which would attract and retain players.