Assyrian power and wealth were a result of: the loot
from war and the trading empire they developed
the celebration of violence and bravery
the use of iron in tools and weaponry
the development of politically rich city-states

An informal structure in a bureaucracy would be something like so-called "office politics". where there's a formal structure set up for the organization, but then an informal subculture as well that has a way of organizing the bureaucracy further. this can be positive because it sets up an added degree of organization, albeit informal, within the bureaucracy.

A. they replicate studies