I think all airplanes increased their autonomy during the war, and I see a lot of difference between Escorts, up to +18 rank, with Interceptors.
I study everything you say about technologies.
What you say about the armored I think can be done, in the same way as the movement factor of the Russian armored, you can give them 10STR and a corresponding price, and on a specific date they go up to 20STR, and on another date a 30STR. It is also necessary to take into account for the price of the unit, that later it will cost them to raise the STR by 60% of the purchase price.
And everything else that you comment can also be done with events, or adding it directly to the scenario.
I think Syria was invaded so that the axis would not help Iraq. It was not in the Allied plans to invade Iraq or Syria until the coup in Iraq, if I am not mistaken.
Diplomacy could be activated for PBEM, we could increase loyalty towards one side or another with events, depending on who is attacked or what is done, plus the random factor of the influence points could give a lot of play.
My native language is Spanish, and no English language mastery, sorry.