Well, here is what I think needs to be done:
1) Tanks should have a small "radius of engagement" in the rear 180 degrees. That is, they will not engage distant non-threatening targets in the rear hemisphere.
2) If a threat should appear in the rear hemisphere worthy of the vehicle's attention, the hull will also rotate to face the threat, bringing the target to bear more quickly.
3) Tanks will not rotate their turret in the direction opposite to that in which the hull is turning.
4) Turret speed will be factored into the tank's targeting priority. That is, a tank will prefer targets closer to the vehicle's front.
5) Some memory of a known threat that moves out of LOS should stay with the tank. I played a silly game of "ring-around the rosie" with a Stuart in this scenario. The Stuart hid behind a burning halftrack literally 1 yard behind my Tiger. I backed the Tiger up to unmask the Stuart. Meanwhile, the turret rotes 180 degrees away from the Stuart to shoot at a squad cowing in some trees 200 yards away. The tiger backs up, pushing the halftrack aside, and revealing the Stuart. The turret starts to swing back again to face the Stuart. The Stuart speeds around, hiding again behind the halftrack. My turret instantly swings away back toward the squad. Repeat for two turns until I finally pushed the wreck far enough back so that the Stuart couldn't hide there anymore. At no time was the Stuart more than two or three yards from my Tiger, but the gun would not stay pointed in its general direction. I would have expected the Tiger to ‘know” the Stuart was behind the halftrack and not swing its turret away.
Once again, let me state that I think CM is an outstanding game – I just think we have an issue here which needs attention. I played this scenario half a dozen times before giving up in frustration.