And Faust has been done so often, I'm sure that is why Lucas avoided it. Anni's turn started with the slaughter of his mom's killers in Episode II. It continued with his breaking of his training to have an affair with padme. Further along when he killed Count Dooku, which is something even Dooku would not have done.
After 9-11, my first thought was to nuke the bastards and if we had, we would have irreversibly gone over to the dark side. I'm glad for our compassionate, and christian president who had the morals and good sense not to do that.
Lucas did not want Faust. I think he wanted to show the difference between Christians bringing down the Roman empire and becoming the dominate religion for centuries and Hitler almost conquering the world. There were two very different paths to power.