Did the Two Powers Tradition Prefer Deuteronomy's Account of the Sinai Theophany? Who Do the Orthodox Use Exodus Against Deuteronomy in the Mekilta Against Their Interest in Deuteronomy?

From heaven he made you hear his voice to discipline you. On earth he showed you Ishu (his fire) great, and you heard his words from out of the fire. [Deut 4:36]  

Has anyone ever argued that Deuteronomy is older than Exodus? It's not just the retelling of the Ten Commandments. There are two other factors to consider (1) the two powers controversy in the late first, early second century and (2) the fact that someone in the fifth century had to have assumed thr role of prophet like Moses (Deut 18) in order to write the story of Moses' birth and death. The two powers controversy makes clear the Ten Commandments existed independently and before the Torah.

Moses received ten utterances written with fire by God's fire (so the Samaritans) and also added laws ny his own authority which weren't from heaven. There were clearly two powers (one in the fire =ishu, one in heaven = the voice) at Sinai. The rabbanites essentially argued from Exodus against Deuteronomy to demonstrate that there was one rather than two powers or at least that there was monarchia in heaven.

The fact that Exodus is used in the anti-two powers literature against Deuteronomy is only half the story. Deuteronomy not only references two powers in the Sinai theophany but also records God as promising "one like Moses" when the Israelites beg for the two powers to go away "lest they die." Deuteronomy writes:

The Lord your God will raise up for you a prophet like me from among you, from your fellow Israelites. You must listen to him. For this is what you asked of the Lord your God at Horeb on the day of the assembly when you said, “Let us not hear the voice of the Lord our God nor see this great fire anymore, or we will die.” The Lord said to me: “What they say is good.  I will raise up for them a prophet like you from among their fellow Israelites, and I will put my words in his mouth. He will tell them everything I command him. I myself will call to account anyone who does not listen to my words that the prophet speaks in my name. But a prophet who presumes to speak in my name anything I have not commanded, or a prophet who speaks in the name of other gods, is to be put to death.”

But the parallel passage in Exodus not only corrects the two powers reference (by saying there was only one power) but also fails to mention the Ezra-like figure to come:

When the people saw the thunder and lightning and heard the trumpet and saw the mountain in smoke, they trembled with fear. They stayed at a distance and said to Moses, “Speak to us yourself and we will listen. But do not have God speak to us or we will die.” Moses said to the people, “Do not be afraid. God has come to test you, so that the fear of God will be with you to keep you from sinning.” The people remained at a distance, while Moses approached the thick darkness where God was. Then the Lord said to Moses, “Tell the Israelites this: ‘You have seen for yourselves that I have spoken to you from heaven: Do not make any gods to be alongside me; do not make for yourselves gods of silver or gods of gold. “‘Make an altar of earth for me and sacrifice on it your burnt offerings and fellowship offerings, your sheep and goats and your cattle. Wherever I cause my name to be honored, I will come to you and bless you.  If you make an altar of stones for me, do not build it with dressed stones, for you will defile it if you use a tool on it. And do not go up to my altar on steps, or your private parts may be exposed.’

Indeed the Exodus narrative proceeds to introduce a series of new laws on top of the ten commandments which the two powers tradition (and Christians) originally rejected as not being from heaven but established only on the authority of Moses.

But let's look carefully. The Deuteronomy narrative seems to have a whole different understanding. Notice the two powers reference - "Let us not hear the voice of the Lord our God nor see this great fire anymore or we will die." The two powers heresy discussion consistently utilizes these texts - Exodus and Deuteronomy - and the differences between them. Whereas Exodus is only interested in establishing the fact that God gave Moses a series of laws above and beyond the familiar ten commandments (familiar before Ezra's introduction of the narrative Torah) Deuteronomy curiously seems to prepare for Ezra coming the name of Moses to write the Law.

I can't help but feel that Deuteronomy in some way either preserves information about a source before Exodus or is more original, closer to the 'excuse' that Ezra used to write the Torah (i.e. that he was the second Moses). In other words, not only does Exodus only mention the 'voice from heaven' (and not 'His fire' = Ishu) but goes out of its way to correct the implications of that 'original' passage in Deuteronomy adding in bold:

‘You have seen for yourselves that I have spoken to you from heaven: Do not make any gods to be alongside me."

Instead of the two power theology at the heart of Deuteronomy:

Let us not hear the voice of the Lord our God nor see this great fire (= Ishu) anymore

In other words, Exodus knows that 'Jesus' (viz. Ishu) is present in the original narrative and corrects the understanding by precluding the possibility of a second power. This is probably why the mekhilta juxtapose Exodus against Deuteronomy. Indeed a mekhilta is properly defined as the rules of interpreting the Book of Exodus. But what did the heretics believe? Could it be they developed their opinions exclusively from Deuteronomy? Now to research whether there are any traditions or scholarly studies which argue that Deuteronomy is older than Exodus.