I think to make this game more fun and realistic, you should bring back the option to trade military units. In the real world, many powerful countries sell cheap, old aircraft, support and armored vehicles. I think if players could sell those units to other countries, we could profit. Now here's my other suggestion. When we progress through the tech trees, the game shouldn't transform already-existing units into the new upgraded unit. They should stay the same, and we'd have to mobilize the new upgraded units in order to use them. We could then sell the old units for profit and build more of the new advanced units. We should also have the ability to choose which generation of any of these units we want to mobilize. So, if we want older units we could mobilize older units and sell them or do whatever with them, or we could choose to mobilize the newer units. I think there may be some problems with this, but you guys could probably find a solution.
And this time, when we sell a unit to another country, the unit should stay as its original doctrine, but the flag should be changed to the country it now belongs to.
And this time, when we sell a unit to another country, the unit should stay as its original doctrine, but the flag should be changed to the country it now belongs to.