There are literally Kilometers of those small stone walls that litter the landscape. AI vehicles constantly get stopped by them/ flipped at the worst.
If they would be destructible (like fences, or those clay walls in A2:OA) we would have way less trouble commanding some tanks across open terrain.
Those walls stopping a big vehicles is completely unrealistic anyway, they are just stacked stones basically.
It would be great idea, but i would add some particles effects for destroying this stone fences. But problem is, even destructable objects (like bushes!) can flip tank upside down. Its a little unaccepatable dont you think? There is an other changes what you (Bohemia) can do, even as temponrary - Force crew to not disembark when tank is flipped (or give 5-10 seconds limit, if tank will be still flipped, then crew can disembark) and give us an option (something like self interaction menu, or (ai menu) http://www.armaholic.com/page.php?id=22380 and giv there option "reset tank position". It would be like developer tool, but it would help player (at least, maybe something to help AI?) to avoit disembark straight undern enemy small arms fire.