I liked how borders were made in Unity of Command - it was perfectly possible to see terrain while knowing the ownership of it. I also liked how map ownership changed rapidly, creating encirclements and counter-encirclements, without the need of going from one empty province to another, which I find somewhat silly most of the time. I mean, there were many situations where Soviet forces were behind the advancing Germans forces and had to fall back through enemy-controller area. Enemy didn't have enough forces to form solid front and many units slipped through to their own lines.