TS generally works really well for us in ET. As 3 golds plus lap infant, we always book A,C,D in a given row. On all 3 flights where we have done this, B and E have remained empty. We figured that in case of full flights, we would ask if the person in B wouldnt mind swapping with the person in D, as they are likely to prefer an aisle to a middle.
Playing the system? Yes, but for once, happy to find a BA system that works for us.