I was thinking about mod ideas and decided it would be pretty cool if there could be a side added to the existing 3. I know it would be a LOT of work but it would be really awesome to add all new units and buildings. If a new country couldnt be added then maybe one could be replaced. You could play as Russia instead of China!
yes it is possible in fact i have done it but i am tweaking my USSR side still
Only drawback is that the new side will be unusable by the computer. There is no AI support for mods.
what about using chinas AI for Russia, you might have to change a few things of course but it might work