Mike,
It easy to debate all this after seeing a brief film clip, but a trained recovery mechanic would not put their equipment in that position. Indirect pulls are one of the set ups they are trained to do (in the army that is). Although the dozer went over the bank, its centre of gravity and stability on tracks was far greater than the AEC. From what I saw, with the RB tracks at right angles to the pull, the operation was spot on and I guess the dozer and AEC drove straight out without causing themselves or the ground any more damage.