In terms of what was taught to the faithful, little changed.  Yes, there were grand arguments on Christology and fights and schisms based on fine points of meaning, but the teachings found in the Gospels and what was communicated to the Church went along with little, if any, change.  
That's why I used "teaching" v. "theology".  
Even Canon of the mass had no significant change, in the West, for the 700 years prior to Trent that we can trace (the Boniface Canon, for instance).  The Tridentine removal of various forms of Western liturgies was much more about standardizing (thanks to the Franciscans) than ridding the West of something truly aberrant.
I stipulate to the Advocate, but not on the subject of wholesale change.  Something truly dogmatic (not merely what one believes is dogma) cannot change if it is guided by an unchanging God.