Our original paper tried to characterize the richness of the teaching repertoire of expert human teachers and to give a sense of how far there still was to go in the development of pedagogic expertise in AIED systems. It considered three ways in which more expert teaching strategies and tactics might be developed. These were via (i) the observation of human expert teachers, (ii) theoretical derivation from learning theories, and (iii) empirical observation of human and simulated students. This paper reflects on the original paper and briefly sketches progress since 2001.