Sounds fine on first look but ....
As pilots are notoriously unable to see behind them, this will still need somebody on the ground to either direct or control the equipment and steering at pushback. How complex could that be ? Or are we going to put video cameras in tail and wingtips ??
There is a weight penalty for every aeroplane which needs to be offset against fuel. Will one pushback be more expensive than lugging the equipment (say 500 kg inc batteries as I somehow doubt an APU providing enough amps to drag the aeroplane about) on a 12 hour plus sector ?
This will need to be fited on every aeroplane to be effective but a tug can push ... what ? a plane every half hour ??
Just musings ......