Although John Cassian spent a decade or more living with the Desert Fathers, people do not trust his writings to be an accurate reflection of the Desert Tradition. Some say that Cassian’s writings are too philosophical and theoretical at times, too sophisticated. The pure and true Desert Tradition of the poor, simple Coptic monks was not like this at all.
The evidence seems to be to the contrary, however. The letters of St. Antony are one example of Coptic literacy. And Didymus the Blind is an example of illiterate sophistication. Furthermore, teachings of Cassian and Evagrius that many think are antithetical to the “pure” Desert Tradition are frequently found in the teachings of the Desert Fathers.
The second difficulty people have with Cassian is the fact that his Conferences are so long. As stated originally, I do not see this as a problem at all. Just because the Apopthegmata, or Sayings of the Desert Fathers, are all short does not mean that these same men did not sometimes give longer discourses.
Finally, people point out that John Cassian himself acknowledges a certain amount of modification due to the differing circumstances of monks in Gaul as well as his faulty memory. This is true, but we cannot fault Cassian for any resultant changes; Cassian was not seeking to write a history, such as the History of the Monks of Egypt or the Lausiac History. He was seeking to engage with a tradition and pass on the wisdom of this tradition to people in a different situation. I believe that he effectively did this without compromising the Desert Tradition.
Indeed, as I read Cassian, Evagrius, the Sayings, and other things, I see how big this tradition of the Egyptian desert is. They are not all in agreement on every point, but they are still standing within the same flowing tide of teachings and practices handed down from master to disciple, beginning with Antony — though Cassian would tell us that it began with the apostles. It is the handing on of wisdom and actions that makes a tradition. One can be creative and true within a tradition at the same time.