Hi
Since the time scale of the game would allow a tank to turn its less vulnerable side towards incoming fire after the first shot, how about a penalty to armor or a bonus to shooting for combined fire coming in through at least two non-adjacent hex sides? It is quite hard to protect your soft backside from fire coming in from more than one direction.
Some tanks should be immune to this because they have good armor all around, and some should be even more vulnarable because they are virtually open at the back (some SP guns, tank hunters and semoventes come to mind).
This would simplify the matter greatly, emphasize maneuver and remove the headache "what-facing-to-choose-at-the-end-of-a-move". The only thing not covered by this little rule is ambush by AT guns or tank destroyers as opportunity fire during your opponents move.
"I am not feeding the troll, I am not feeding the troll, I am.....garr." My thoughts exactly.