Yes, modern day Christianity is similar to other religions on that regard. That is why the thread subject question. Would you agree that Christianity (true Christianity) places more emphasis on 'right belief', than the others. Or at least the others regulate 'right belief' as less importance as when we get down to it, they do not belief in the incarnate God who came to take our sins away.
No, I really cannot agree that "
(true Christianity) places more emphasis on 'right belief' than others". As I tried to relate previously, the true Church has emphasized BOTH right doctrine as its foundation and proper application of that doctrine to life. Since you mentioned the post-Reformation church as having more emphasis upon doctrine, let me counter that by holding up the Puritans as exemplary dogmaticians who also stressed living in holiness before God. They are sometimes referred to as "doctors of the soul" who focused upon the inner man. Again, let me point out that it was the Reformers and Puritans who wrote the great Reformed confessions and catechisms AND who made great efforts to distinguish between a true confession and false profession by the examination of one's life. So, it was BOTH and not either/or.

My impression is the the RCC controlled the dominant Christian positions before the Reformation, and they were in grave errors over many doctrines. Let me ask a question. Was it a gradual move in its heresy or was their one particular event that cause the move toward heresy. When did the RCC take control over Christianity. They were right in many of their early creeds and council results, but did any of the councils address the 5 Solas. What about grace alone. Did any creed or council addressed that? Maybe I need a good lesson on the development of doctrine before the Reformation.
1. Yes, Roman Catholicism was the dominant force before the Reformation but there were other powerful forces as well, e.g., Eastern Orthodoxy which rejected Rome's taking authority in the West in the 11th century. Both claim to be the "original" Christianity dating back to Christ. But it was around 440 AD that Pope Leo established his dominance over the Latin churches while Pope Dioscorus, St. Cyril's successor as Pope of Alexandria was head of the eastern, mostly Greek, churches. But wasn't until 604 that Gregory I was declared to be the "universal Bishop", but refused the title of "Pope". His second successor Boniface III, however, assumed the title in 607.
2. Heresy most always is a gradual falling away, and continues to be so in our own day. Doubtless, this is why it succeeds as it has. The entrance of heretical doctrine and/or practice begins with very small steps, e.g., the simply questioning of the established doctrine of the Church, progressing to "discussions" of possible alternatives and eventually to the open repudiation of them. The major heresies of the RCC surprisingly did not appear until much later. Here are just some of the later developments within the RCC:
- 1079 - Celibacy
- 1090 - Rosary
- 1215 - Transubstantiation
- 1439 - Purgatory and the Seven Sacraments
- 1545 - Declaration that Tradition was of equal authority with the Bible
- 1854 - Immaculate Conception of Mary
- 1870 - Infallibility of the Pope in matters of faith and morals
- 1965 - Mary proclaimed Mother of the Church
There is, or course, a lengthy list of additional errors, but the ones above should be sufficient to show the gradual decline within the RCC from orthodoxy.
3. I do not recall an early official Creed that dealt with the issue of Sola Gratia or Sola Fide. History does record various groups who opposed the synergistic soteriology (semi-Pelagianism) of Rome before the Reformation. It was then that this latent opposition came to a head thanks to Martin Luther and a few other less known individuals. The rallying around Luther demonstrates that Luther was not a 'Lone Ranger' in his objections. But he was raised up by God to be the one who openly and publicly challenged Rome's errors in doctrine and practice.
4. There are several excellent books that would provide the history of doctrinal development, e.g., Louis Berkhof's
The History of Christian Doctrines, Phillip Schaff's large
History of the Christian Church, and others.