Is it a hard question to answer because you probably know that if you say yes, you will have to concede that genuine Christian faith is found outside of Roman Catholicism, and if you say no, you will be labeled a bigot and prejudiced? The middle of the fence can get uncomfortable, can't it?
Your answer makes assertions that are simply not true. First of all, not "ALL" the church fathers were Roman Catholics. You can use the word "catholic" to describe those who held to the universal Christian faith as taught by the Apostles of Jesus Christ, but that would not be the same faith that is taught in Roman Catholicism today. It's just not - no matter how much Catholics want to believe it. Many Church fathers were Greek, some were African, not all were Roman. If you read the writings of these early leaders in Christianity, you would see that they often disagreed over details of the faith - though they were unified in the main tenets as Scripture taught them.
The Roman Catholic Church selectively and over time took various teachings of some, rejected other teachings of the same and gradually developed what is accepted as "Catholic" doctrine today. Some fathers' views were later rejected as heresy when in their lifetime they were acceptable. Many dogmas Catholics believe today were either not heard of by these leaders, held at one time but then rejected or changed by subsequent leaders. There was plenty of "new material" that came up over the centuries.
A good example of that is the doctrine of transubstantiation. William Webster, an evangelical who pays a great deal of attention to Church history, points out (in The Church of Rome at the Bar of History) that early church history presents not just the Catholic view, but most of the views we find today: "There is the literal view of transubstantiation which could be that expressed by Chrysostom; the Lutheran view of consubstantiation, which could be taught by Irenaeus or Justin Martyr; the spiritual view of Calvin, which is closely aligned with Augustine; and the strictly symbolic view of Zwingli, which is similar to that expressed by Eusebius" (p. 122). To the "symbolic view" list, Webster adds Theodoret, Serapion, Jerome, Athanasius, Ambrosiaster, Macarius of Egypt, and Eustathius of Antioch. While they are not exactly household names for many of us, we do know how highly Augustine is esteemed among Catholics. Yet he was not a fan of literal transubstantiation: "'Except ye eat the flesh of the Son of man,'says Christ, 'and drink His blood, ye have no life in you.' This seems to enjoin a crime or a vice; it is therefore a figure , enjoining that we should have a share in the sufferings of our Lord, and that we should retain a sweet and profitable memory of the fact that His flesh was wounded and crucified for us." (On Christian Doctrine, 3.16.24) (from http://www.thebereancall.org/content/home-rome)
Another site, if you are interested, that goes into detail on various early church fathers and their writings about the Real Presence can be seen at http://onefold.wordpress.com/early-church-evidence-refutes-real-presence/.
You may think Newman is the greatest theologian of the 19th century, but that is an opinion. It doesn't mean that everything he said was true. He did, as a matter of fact, come up with the explanation of doctrinal development to try to rationalize the truth that Rome did indeed change doctrine, create new doctrines not held by the early church fathers and which repudiated the previous assertion that the Catholic Church only taught what had been believed everywhere, always and by all (quod ubique, quod semper, quod ab omnibus creditum est). You can read more about that here.
I think you just answered the question of why Newman was considered so great a theologian by the Catholics.
It allows them to maintain the facade of constancy of belief.
I answered your reply and it looks like it was removed by the moderator, for what reason I don’t know. I never personally attacked anyone. I only told you I think it is absolutely impossible for anyone that has an unbiased knowledge of Christian history to leave Catholicism for Prostantism.
I also said the greatest living Christian theologian is named Joseph Ratzinger, who went on to become Pope Benedict 16th. His entire life has been devoted to studying the gospels. He has a genius IQ and I think if Joseph Ratzinger never converted to Prostantism the Catholic Church is the One, True, Faith. If not there is no way on earth that Joseph Ratzinger would still be a Catholic.
End of story.