I don't think we will ever find anyone with whom we will agree 100% on everything. However, on matters of the Church, I don't believe the Apostles would have written the Epistles if they weren't looking to conform the churches to objective truth.
There are still great mysteries to be unraveled and a continuing revelation unfolding--much for us to discuss and discern... but upon the foundations of Christendom, we should be in agreement. It's sad that, in truth, the Reformation split the Church doctrinally when Martin Luther's disagreements were more about ecclesiastical practices. Back to the topic of the thread, Martin Luther had a very strong devotion to Mary. I'm not saying that she is to be elevated as this thread is noting, just that many here have called Catholics to the carpet for our devotions and said they are the sine qua non from which this elevation occurs. I merely point out that if veneration of Mary as the Theotokos were the issue of the Reformation, there wouldn't be protestants today.