I'm reading Michael Angold's Political History of Byzantium 1025-1204 at the moment. There's a really interesting section in there about the search for a new policy under Constantine Monomachos, and it's ultimate failure. I think there's the bones of a discussion here about growth and change in the Byzantine economy, and it's impact on politics. Following Alan Harvey's thesis about growth in the 11th century economy - Constantine Monomachos' administration is fostering this as a route to prosperity, and stepping the atate down from it's war footing - hence the runing down of the themes. I think Haldon has also pointed out that employing professional soldiers ('mercenaries') is a rational decision. I guess what I'm working towards is the idea that there is a nascent blossoming in civil society which is abruptly cut short after Manzikert and the capture of the state by the feudal aristocracy (Comnenus) who run the administration in the narrow interests of their own class.