[Marcello]

"To take out the tank from a battlefield not a problem.
The idea consists in that the tank after repair could continue to be at war."

It's too much time consuming to fit in the game time scale.
This game is designed to deal with high intensity battles fought in a limited time span. Repairs are outside its scope. If game length was extended so that repairs were meaningful then you would have also to worry about the fuel consumption of several vehicles and various others issues.