Moses is a hero, as well as a religious leader, and maybe that is a point of concern. He cannot be seen merely as the man, who cooperating with the Will of God, freed the Hebrews from slavery. He must be seen as "the" Prophet, who transmitted the Decalogue to the entire world-Revelation from God through Moses.
PS I cannot refer to The Ten Commandments without mentioning one of the worst lines in cinematic history: "O Moses, you stubborn, you splendid, you adorable fool!" Anne Baxter's famous line to Charlton Heston-her Nefretiri to his Moses. I am sure both Gibson and Spielberg will avoid such schlock.