Even if your idea is balanced in a way that maintains more or less same wiping power of infantry vs retreating infantry, I think it would be an unnecessary nerf to tank shells and explosives as they should be punishing. Hitting retreat button should not save you from all threats imho.
The issue isn't the effectiveness of wipes, it's the inconsistency of wipes. I agree that pulling off a flank should reward you with a good chance to wipe, but the probabilities with the current "huge RA spike" method are all over the place.