The middle ages were, for most people, a vast improvement over the axial age. The collapse of empire broke the war/bullion/slavery complex. This also lead to increased political stability, and a localization of political power. The abandonment of the cities meant that each agricultural worker has less mouths to feed. Farm productivity also improved. Coinage evaporated, but the law codes imply a fairly strong credit-based market emerged.
Slavery was widely abolished during this period, not to be re-instituted until the colonial age.
A side question– where did all the coins go? In India at least, they went into the temples and were melted down to make statues and gilding. Thus to re-create them, an (evil) emperor would have to melt down holy items. Which some did, of course.