I especially like the small touches: like the algorithm that prevents grass and bushes from growing in roads, the ditches at the edges of roads, the new bridges and culverts, the shade under trees etc. And it is nice that they have kept the frame rate (on my machine at least) the same or better.
Oh, and I like the addition of using the joystick to pan the commanders view in the tanks. Nice (if a bit confusing at first as the commander doesn't pop up looking the same direction as the turret anymore).