Actually it's a really good idea. With the right overall setups can allow for smaller drivetrains than current AFVs, far better protective schemes, and even the ability to do a lot of minor things without cutting in the engine. If they put in a robust battery system to allow for some small maneuvering, or for the tank to pull away from a shoot and scoot position BEFORE cutting in the engine, you've got a very potent combination.
GM of Koingerdammerung, the Beginnings
Lieutenant Tac, Weapons Platoon