Personally, one of the more important factors which contribute to my loss in a game is the support weapon control.
Typically, what would happen is that when an enemy blob is approaching, I would select my HMG and right-click on which infantry squad to focus on. Very often the infantry would be moving so fast that I would misclick by accidentally clicking in the gaps of the moving infantry models. Consequently, the machine gun would set up and then set down, which could cause you to either force you to retreat or lose the machine gun itself. This is especially penalizing for MG42 which has the longest set up and set down time.
Another example is when you right-click a tank with your AT gun that eventually goes out of your range, the AT gun would set up, rotate so that the tank is on the edge of the cone, then set down. Naturally, the tank would move again and the AT gun would be in a constant aforementioned cycle of setting up, rotating, setting down.
What I would like is to see an ability for HMGs and AT guns to not move unless the retreat button is pressed. Alternatively, something akin to holding the Control button to not move when giving an order that would otherwise result in movement. All of this itself isn't bad, but it can harm you significantly and hamper you in the long game. This is a simple Quality of Life change I'd like to see because it would improve my gameplay tremendously.