Hi Ken,
It is so hard to know what happened in those early years and how Paul/Saul (or the Origenists) fit into it. However, I don't really see that what I think of as the Esoteric Egalitarian branch of Christianity represented by Bogomilism/Catharism and their successors, OR the Exoteric Imperial branch of Christianity with power centers in Constantinople, Rome, and elsewhere held onto the full essence and purity of the original message. So, the issue may be moot either way.
Christ warned of the dangers of trying to put the "New Wine" into old wineskins, yet that is the way it has always worked. We try to fit what we have received into the context of our preexisting beliefs. The original Jewish believers tried to fit it into their context of Jewish legalism under the Mosaic Law. This problem is addressed in the New Testament, and didn't last very long. The Gentiles then did their best to fit it into their preexisting paradigms. The Greeks were perhaps the most benign in their influence, as they merely sought to understand it in the context of their own philosophical beliefs, particularly Neo-Platonism. (Origen was part of this). However, they were soon quashed and assimilated by the dominant and control minded Romans (who by that time had divided the empire in two with its primary surviving power base in Constantinople). As far as I can tell, the Imperial Christianity of the Latins/Romans has become the basis of the current Orthodox, Roman, and Protestant "flavors" we know today. However, alongside this development of the more hierarchical exoteric stream of Christianity, it appears that there was a countervailing stream of egalitarian esoteric teachings and believers that survived in the Eastern Roman Empire and beyond. However, while purer in many ways, I do not see this strand as being unaffected by the hands and minds through which it passed. They seem to have been greatly impacted by, and sought to fit their faith into, the "wineskin" formed by the ancient Dualism of the East (Zoroastrian and otherwise) as well as including some random Gnostic elements. Christianity is certainly susceptible to interpretations congruent with these teachings, but not without distortion IMO.
Unfortunately, the dialectical clash (thesis vs. antithesis) between the Imperial Exoteric and the Egalitarian Esoteric (which are once again my own way of looking at these two) when they finally met did not arrive at a benevolent synthesis of the best features of both. It did result in some reforms in the former, which found itself shamed by the selfless purity of many of the best of the latter. However, for the forces of the egalitarian/esoteric stream of Christianity represented by the Bogomils and Cathars, there was only brutal annihilation. The erasure of these movements amounted to such a complete and thorough extirpation that we do not today even have trustworthy and reliable samples of their full teachings. The more mystical may never have never been committed to writing, however, even with this proviso it is a shame that so little has survived.
In terms of Paul/Saul, I do not really know how much influence he had on the Cathars/Bogomils as I have read contradictory things on this. Some posit a strong connection between Bogomilism/Catharism and Marcionism, which extolled the Pauline teachings. There are definitely some common elements, so I can understand the arguments. Others see a strong connection to the Apostle John and the Johannine School of early Christianity (contra Paul). Once again, there are definitely some arguments for this. Likewise the Origenists and others. So much is lost to us historically speaking. We may never be able to ferret out the answers to all of these questions.
Cordially,
S&S