I’m afraid you’ve fallen into the false teaching of Archbishop Gregory of Denver and many others against the Great St. Augustine. Orthodox people are not free to reject him as a saint, since two ecumenical synods, the fifth and sixth, explicitly refer to him as a saint. Here is a list of the “eight heresies,” that St. Augustine is often accused of.

(1) the Filioque, (2) original sin, (3) the redefining of baptism, (4) predestination and irresistible grace, (5) the disavowal of free-will, (6) confusion in understanding the differences between essence and hypostases and the energies of the Holy Trinity, (7) theophanies and created energies, and, (8) the validation of heretical baptism.

Now, St. Augustine was canonized in about 500, and fully accepted, both east and west. Augustine wrote nearly 200 full folio volumes of work. The Orthodox know only a tiny fraction of these. Unfortunately, I know Augustine's writings, and, ultimately, none of the heresies you mention stand well with St. Augustine, and many of these were also committed by eastern writers, including Gregory of Nyssa. Remember, Augustine was writing against the Pelegians, and it is in this context that you must understand him. Few Orthodox have even bothered reading the 800 pages of the City of God. It took a long time before Augustine was translated into Russian, and few of the Old Orthodox have anything to go on.

Let me give more detail, concerning the infamous “eight heresies”:

1. I know De Trinitate very well. He does not teach the filioque in it. Sometimes, the Latin can be deceptive. The only real thing you can point to is that he likens the Trinity to the family: Mother and Father making the Son. This is a simile only, and not dogma. The creed in the Liturgy said by St. Augustine did not contain the filioque as no western creed did at the time. Remember, he's trying to defend the Trinity against the pagans. That's his mission. Hence, he uses many literary similes in order to do this. Since the filioque controversy did not even exist at the time, it is anachronistic to speak of it. The creed of St. Athanatios also mentions the filioque though again, this may be a later interpolation. However, later, the Roman Catholic sect tried to use this work to justify the filioque. Though that was a tough road, and, as you know, several popes condemned the filioque, such as Leo III, precisely on the basis that St. Augustine did not teach it (among other reasons).

2. You are correct on the inherited guilt thing. It was an error, but hardly a heresy. Many of the western fathers were teaching it, but in the context of attacking the arch- western heretic, Pelegius, who claimed that no guilt, or even propensity to sin, existed at all. Again, context here.

3. This is the same as #2. Of course, adult baptism does forgive sins, infants, no.

4. St. Augustine, as with many western fathers, went back and forth on predestination. It is rejected in the COG, though I need to look this up for you. He is struggling with the concept of God's full knowledge of our life with the concept of free will. He wrote an entire work on this. Few had worried about this prior to St. A, and he was the first to write a substantial treatment on it. Again, there is a western context of this that did not exist in the east. Controversies came up in Africa and Gaul that did not arise in the east. Keep in mind also that the Arians were extremely strong among the Germans tribes in Gaul, which provides the backdrop for some of St. A's writings that did not exist to any great extent in the east.

5. My friend, please re-read that work. He does accept Free Will, though he never quite makes it fit with God's complete knowledge. It is a struggle, and it is something that St. A fully admits he struggles with. You seem to be looking for things to attack him on, but forget about the personal struggles he's going through here. He is arguing with pagans, not Arians or other pseudo-Christians. Thus, the argument is going to be different. Keep in mind he is also struggling with his past as well.

6. You’re all wet here. The Orthodox doctrine on the Spirit was never developed in the east until Basil. That was part of the conciliar struggles in the 3rd synod. Give St. A a break, he did not have much to go on here, as we do today. As much a I loved Fr. John [Romanides], he refused to admit that St. Augustine is listed as a saint in the 5th council. The west was Orthodox throughout the first millennium. Augustine was not attacked in the east until the 19th century. The essence/energies distinction was not formulated in the east until the controversy on Athos on heseychasm long after the death of St. A

7. There are still great controversies over this question. Augustine is writing in the 400s, when this stuff was still very much a live issue. Nothing had been settled here.

8. Like it or not, this is the African Orthodox position at the time. The case was not closed on this at the time that St. A wrote.

St. A never said that “Rome has Spoken, the case is closed.” It is not found in the sermon you mention. Rome, of course, was Orthodox at the time, so it really is a moot point.

Dear Friend, I'm terribly sorry for my tone here. You are a good man, but I believe you have not spent the time necessary on the massive writings of this man. I have (for better or worse). He is a saint, canonized east and west. He is mentioned in the 5th synod. His writings engendered many controversies. So did all the saints. Do you not recall the possessor non-possessor controversy? Both men were saints, both loathed each other. That's how it was, and it was common. St. Jerome was also trashed by many Orthodox at the time of his writing. This is not an argument, but is typical of the age in which St. A was writing. St. Ambrose claims that the elements in the liturgy are sanctified by the words of institution, not the epiclesis. Do you reject him too? St. Gregory of Nyssa taught that Hell was not eternal, so did St. Jerome. Do you reject them?

Similarly, in his epistle to the Fathers of the same Synod, St. Justinian (†565) includes, in his references to the “holy Fathers,” Augustine among such luminaries as Sts. Athanasios (†373), Basil (†379), Gregory the Theologian (†389), Gregory of Nyssa (†395), John Chrysostomos (†407), Cyril of Alexandria (†444)

St. Photios writes, "Read through Ambrose or Augustine or whatever father you choose: which of them wished to affirm anything contrary to the Master's voice?" And further on, he says:

If those fathers who taught such opinions did not alter or change the correct statements, then you who teach your word as a dogma–again, this is another slander against your fathers–bring your own stubbornness of opinion into the teachings of these men." And again, "Though they were otherwise arrayed with the noblest reflections, they were human. If they slipped and fell into error, therefore, by some negligence or oversight, then we should not gainsay or admonish them. But what is this to you?

Generally, the attacks on Augustine are motivated by an irrational hatred of anything western. Never mind that the west and east formed one church for the first millennium, and the Orthodox calendar is saturated with western saints. The Greeks generally reject the western rite, even though the Sarum liturgy was the liturgy of St. Gregory, a saint in the east and in the west. Most of the Russians do so as well, though they do not have a theological leg to stand on. It’s pure emotion and vitriol. Jerome, John Cassian, Methodius and a whole host of others regularly went back and forth east to west, cross-fertilizing and enriching the faith. The east/west divide did not became dominant until after the 4th crusade (1204, etc.). St. Leo the Great, the dominant force at Chalcedon, was an admirer of Augustine. If you think that one needs to accept everything in Augustine’s 200 volumes, you’re nuts. But that goes for all saints. St. Nikodemos the Hagiorite includes Augustine in his list of saints. Here is the troparion for Augustine, composed in the 7th century: “O blessed Augustine, you have been proved to be a bright vessel of the divine Spirit and revealer of the city of God; you have also righteously served the Saviour as a wise hierarch who has received God. O righteous father, pray to Christ God that he may grant to us great mercy.”

Here is the entry from OrthodoxWiki:

The Fifth Ecumenical Council, held in Constantinople in A.D. 553, listed Augustine among other Fathers of the Church, though there is no unqualified endorsement of his theology mentioned (just as there is none for most saints of the Church):

We further declare that we hold fast to the decrees of the four Councils, and in every way follow the holy Fathers, Athanasius, Hilary, Basil, Gregory the Theologian, Gregory of Nyssa, Ambrose, Theophilus, John (Chrysostom) of Constantinople, Cyril, Augustine, Proclus, Leo and their writings on the true faith.

In the acts of the Sixth Ecumenical Council (not yet translated into English), he is called the “most excellent and blessed Augustine” and is referred to as “the most wise teacher.” In the Comnenian Council of Constantinople in 1166 he is referred to as “Saint Augustine.”

It seems to me that if you reject the sanctity of St. Augustine, you are rejecting the 5th and 6th Ecumenical synods, both of whom spoke of his sanctity. There really is no third option.

Fr. R