I would agree that it's more feudal than based on the Byzantine Empire.
I think the reason Taldor is so decadent is that Oppara thinks that it is safe and doesn't care what happens "out there" as long as the money/taxes/goods keep flowing into the city. I would go so far as to say that they think their armies can stop anything and aren't worried about it. In this, I think they are deluding themselves.
I further agree that each Prefecture is subdivided into many different areas. I see the ones near Oppara, or to the north but not northeast as being the most desirable with the borders being least desirable. Within that division, I think the borders are struggling more than the capital is willing to admit.
(For some reason, I'm imagining the dust bowl conditions of the midwest compared to what Washington DC thought was happening but I'm sure there's a better historical analogy.)
However, if it is Byzantine, then it means these prefectures are up for grabs in who rules it every so often, and there is no hint of that from what I read. It could be implemented, though, and would be a source of politics as each family strives to make sure they have the desired prefectures. However, if it's feudal, as we have said, than it's all hereditary, in some manner, and fixed in where each noble family is.
What do you think? I personally like the idea of it being Byzantium and the chance that a family might lose prestige and wealth if they lose control of a prefecture. They will still have one, but not one that is seen as prestigious. It also adds a layer of politics that could turn deadly to keep what they have.
