I've got an original backstory for the entire galaxy that channels into the prequels I am writing and is (hopefully) a better prelude than anything made under Lucas after 1999. This even applies on a technological level; such elements we took for granted in the OT like lightsabers, hyperdrives, and sentient AI simply did not exist until late in the Republic era.

So basically nothing before ANH matches the canon of the Lucasverse. Some things like Coruscant have been retooled somewhat, and certain background elements like the Trandoshan race and the planet Taris also factor in. But anything that is directly and specifically reminiscent of any of the three PT films or anything that branches off of the PT films is a no-go for my rewrite.

Though I must admit the basic concept of Plagueis has some merit, the grand-daddy of evil if you will. Or was that supposed to be Bane?