I'm not exactly sure what you mean by "elevated". Certainly, you realize that the "Gospels" were written at a later date than most of the epistles. The teachings of Jesus were told and retold verbally for many years prior to them being written down for posterity. Paul, for example, learned not only from the followers of Jesus what he spoke but from Jesus himself. So, in that case, what Paul wrote WAS the word of Almighty God just as the case of the writers of the Old Testament including Moses and the prophets (major and minor ones).
I assume your point in stressing this "preeminence" of scripture is to try to prove that what is written that Jesus said overrules any subsequent revelation written in Scripture and, if this is your point, I strongly disagree. Just as your church teaches progressive knowledge, there was progressive revelation. What was revealed as truth to the early Christian church was new compared to what had been spoken of before Christ came. Different audience, different covenant, different purpose - but still the truth God intended to be made known and which he has preserved even until this very day. And God does not contradict himself. It is often our own misinterpretation that causes the conflict. God's word is truth - He knew what He was doing when He entrusted mere men to record his truth - and He ensures its protection from error.
In the words of Jesus, man should not live on bread alone but on every word that comes from the mouth of God. The quotations of Jesus are considered the direct words of God. They should surpass the musings of ordinary men, even if they are considered Scripture. The Jews considered the Torah to be of more importance than the rest of the OT, true? And the justification of the Protestant OT is that the Jews knew it better than the Christians...