Wrecks would be smoking as was typical for recently destroyed tanks, or missing their turret (should the vehicle have one) or on fire, otherwise you might spend 15 mins hitting a dead tank.
It is not intended to help either the attacker or the defender, but to add a level of realism to the ground battle.
Also the wrecks would be on a TIMER. They would disappear after say, 15 minutes (adjustable).
This was not originally intended for the MA, as battles there can last a long time and be quite massive resulting in large frame hits in areas such as Tank Town.
Currently alot of the Special Events are starting to include more vehicle combat. Recent FSOs have done so and the next scenario
"Dawn of Battle" www.ahevents.org will likewise have vehicle combat.