No need to misdirect. I just don't like to retread ground that has been so thoroughly covered by others... and there's really no way to do justice on this forum. If you really want an exhaustive conversation on the subject, you can read here.
LOL
However in the very lengthy Apologetic link you gave me I found no good argument to explain Augustine's apparent "rethink" concerning Peter and the Rock.
For example:
Augustine was not steadfast in his interpretation of Matthew 16:18. Above, Augustine equated the rock with Peter's faith, Peter's successors, and Peter himself. It was during his controversies with the Manicheans, Donatists, and Pelagians that he emphasized the role of Christ and identified "this rock" with Christ. In his dealings with the Manicheans, the nature of God was in the forefront; with the Donatist, it was the nature of the Church and clergy; with the Pelagians, it was the nature of grace and its originator, Jesus Christ. Augustine equated "this rock" with Christ not to downplay Peter's primacy, rather to emphasize Jesus Christ. Against all these heresies, Augustine stressed that the Church's foundation and grace rested upon a divine and not a human person. Nevertheless, Augustine remained steadfast in his understanding of Peter's primacy and the primacy of the Roman See. Augustine did not reject the Petrine interpretation, in favor of which he cites Ambrose's hymn, but leaves it to the reader to choose. Simon remains a rock, a secondary rock dependent on the Rock-Christ, for Augustine writes, 'Peter having been named after this rock ' (Retractations 1:21).
I guess you must throw Augustine out with the bath water.
Good luck in finding a forum which is entirely unique and current in it's subject matter.