Yeah, I suppose it's not a good idea to look to the Church Fathers for definitive statements, even though there is great value in their writings. They were theologians, and theologians are likely to have their own opinions. Theology is not doctrine - it attempts to bring about an understanding of doctrine, within the context of the current age. That understanding helps people make the faith their own, so that their faith is not just an obedient acceptance of a list of "facts" they are required to believe.

As I see it in this context, "rationalization" is using intelligence to find loopholes in matters of faith, while "theology" is using intelligence to find understanding in matters of faith. The works of the Church Fathers were theology, not rationalization.

Faith does not require abandonment of intelligence. Many religious traditions encourage intelligent questioning and discussion of doctrine. It's only the fundamentalists who are required to check their brains at the door.

As for doctrine, which is the official teaching of a religious group, I think I'd rely on the Nicene Creed of AD 325 as a fairly comprehensive statement. It is shared by most Christian groups. That's not the case with "the Fundamentals" that Murray cited, which come from a series of pamphlets published with oil company money in the early 20th century. "The Fundamentals" are the source of the name "fundamentalism" and they give a pretty good summary of conservative Christian belief. "Mainstream" Christians have trouble with the fundamentals.