I Just finished the whole campaign and I really enjoyed it!
However there is room for some improvements in some of the missions:
Mission 1: I think I already told you that on my YT channel but the Soviet Naval reinforcements just spawn from the middle of the river which doesn't really make it look good lol , also the AI's could use some build triggers in addition for having all their stuff already prebuilt on the map
Mission 4: The AI was pretty passive in this one and it could def. get some more attack waves
Mission 5: This mission can be broken way too easily, first of all half an hour is waaaaaay too much time for the player to get ready for the incoming enemies , at this time it's easy to prepare some forces and ambush the enemy at it's spawning positions taking out their forces & their MCV's in a few seconds , this unfortunately made the mission a bit boring with all the waiting only to find out you waited so long for only a few second battle... it might be a good idea to cut the timer shorter and also add more enemy units when they arrive.
Mission 7: That was a real great mission only I couldn't figure out how to fire the win trigger at the end, after "running for my life" with Tanya and taking out all the Conscripts I had no clue on what to do or where to go and I got stuck just wandering around the map with Tanya until I commited suicide with her just for fun by blowing up a Nuclear Reactor xD (I really hope that cleaning the whole map completely isn't the key for victory here because it's no stated as one of the objectives)
Overall like I said this was a great campaign and I really had fun with it!
Hopefully we will see that Soviet campaign you are planning in the near future