How widely held, and how well supported, is the theory that the Roman empire failed because of overregulation and overtaxation? It's not a claim I've heard before, but I am about as far from being an expert in late Roman history as it is possible to be. In particular, how widely accepted is this theory outside circles in which everything is blamed on overregulation and overtaxation?

Overtaxation is a standard reason given for the fall of the Roman Empire, and I'm surprised you haven't heard of that before. I've never heard of overregulation being a reason; I've never looked into the Roman regulatory state, and have no idea how burdensome it was, or even if it substantively existed.