Tank crews should not abandon their vehicles unless they are completely unable to defend themselves (broken turret or clear threat of blowing up.).
Furthermore, Tank Crews -need- basic repair skills. In real life, Crews are trained to fix a broken track themselves, and perform basic repair works on other damaged parts all over the tank.
Allow them to repair Tracks -at the very least- but make them unable to repair -hull- and -turret-.
They also need to be able to repair their vehicles on their own! Right now heavy vehicles are too vulnerable and easily put out of the fight because of minor damage such as a thrown track, when they should be put back into the fight easily.