Part of M. Barnes and Ayres’ criticism of the “neo-Platonic” Augustine is that Augustine shares more in common with the, by his time, somewhat established catholic tradition than he does any identifiable “neo-Platonic” tradition of the 4th century. This is seen in that his principle for divine unity is not simply an appeal to “substance,” nor even the psychological analogy, but rather the inseparable operations of the Persons. This is very similar to Gregory’s one “Power.”
The divine “work” is an aspect of the one nature. This is true for both East and West, of which there is really no dichotomy at this point in history. If there were, as Timothy Barnes’ (not Michel) helpful book on Athanasius and Constantine’s sons shows, then the two parties would actually be Western/pro-Nicenes vs. Eastern/anti-Nicenes., which is not what folks seem to be looking for today.
Again, D. H. Williams’ book on Ambrose is a good way to get a grasp on the emerging Western pro-Nicene tradition.