Augustine definitely deserves to be listened to. He's not perfect, but got many things right, which is not bad considering he didn't know biblical languages (no biblical hebrew at all) or have the resources we have today.
But you might be surprised to find out that Augustine actually was a YEC. Yeah! The early fathers fought vigorously against the old earth ideas of the greeks, and used the Bible to fight against them. Augustine was perhaps the most influenced by jewish allegorism but he still believed in an instantaneous miraculous creation, and he believe Genesis to be historical narrative. He also believed the flood to be global.
Now most early fathers disagreed with Augustine about the days of creation. Most believed they were literal. Hugh Ross and others have completely distorted the early fathers in this regard, by misunderstanding what the fathers meant by allegory. It was a term closer in meaning to what we call typology. For while the fathers believed that the days were literal morning evening days, they also believed they were types of future 1000 years periods. Thus they believed the world would last only 6000 years. Why? Because they believed in a literal 6 day creation!
And even those who didn't hold to literal days, still were young earthers, and believed Genesis to be literal history, and more important understood that death proceeded out of sin. None of them fell for the old earth ideas of their day. I think old earthers should follow Augustine more closely. He didn't buy into man's ideas about deep time.
Now understand, the fathers are not inspired individuals were not perfect theologians. They didn't have the resource we have today, didn't have biblical languages, and were influenced by jewish allegory quite a bit. Yet, with all that, they still were young earth creationists and fought old earth ideas. The text was just too plain to allow a compromise with greek notions of deep time. Why old earthers like to refer to them is beyond me.
To say Augustine, or any of the Christians before the modern period, were YEC, is totally anachronistic. As it is to say the Greeks were old earth believers.
The Greeks believed the material world had existed eternally, that there was no beginning of time, that there was no possibility of a special act of creation by God - in fact that God could not act at all. In fact the inability of god to act was part of the reason for seeing the world as eternal.
These were the ideas the Church Fathers objected to, in particular the implications of the last part which were cleary not acceptable to Christians. And they have nothing to do with the theory of evolution, and little to do with modern cosmology.
The Big Bang theory was originally objected to by non-Christian scientists as being too Christian a theory - their idea was much more like what the Greeks believed, that the universe is eternal and static. A universe with a beginning and end, in their view, was creationist cod-whollop, just the sort of thing a Christian scientist might come up with.
Of course people living in the 5th century had different ideas about particular physical phenomena. Some people thought that the sun was the center of the universe, or maggots came from rotting meat. These are problems of fact, and it is not surprising that we know some facts that they did not.
The important point is the principles. What are the principles that we need to know about the relation of God to the material world that we perceive? What are the principles we need to know when we consider what Scriptures and the teachings of the Church mean?
I would suggest there are some clear answers there. One is that creation itself is a part of God's revelation, and it will never contradict his revelation in Scripture and the Church. If they seem to contradict, we are misunderstanding one or the other.
The other is that even quite early in the history of the Church, we see that people were comfortable with the idea that the creation account was not to be understood in a strictly historical or scientific way. Some did see it that way, but many orthodox thinkers did not and that was an acceptable position.
I am slightly flummoxed that you say that being influenced by Jewish allegory was some sort of a problem. That would, I would think, allow them to actually read the texts as they were intended, rather than like most modern fundamentalist readers do, which is as if they had been written by people from 19th century America. Ancient people, unlike us, saw allegory as a real and valid way to speak truth. The people who actually write the texts of the Bible down were, in fact, ancient people.
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