I think it would help to define what you mean by "feudalism." In 1974, Elizabeth A.R. Brown wrote an article called "Tyranny of a Construct" that basically pointed out the feudalism was a highly malleable term that could be used to mean very different things depending on the point of view of the writer and the location he was focusing on. She made the argument that the term simply outlived its usefulness. Other historians, such as Susan Reynolds have even rejected the core concepts that made up what people referred to as Feudalism (at least outside of Marxist histories).

I don't think there is a consensus that goes as extreme as Reynolds. However, I do think there's a consensus that, in order to discuss feudalism, one has to understand what they're discussing. So I do think it would help a lot to define what you mean by the term first. If you want more information on what I'm talking about (which might help with the definition you use), I'd suggest reading the AMA on this subject

A definition might be particularly helpful in this context since I've seen writers claim the Themes system is similar to the Feudal system in western Europe, so I'd be curious to the extent the Byzantine Empire avoided Feudalism as you might define it.