I was thinking of completely removing the term Sith. They're never mentioned in the first trilogy, and it's easy to assume Palpatine is simply a wizard that has trained himself in the ways of the Dark Side. This would prove extremely difficult to do with Episode III, but since this the Radical Ideas thread, well, I see that as radical enough.
Likewise, losing the Chosen One/Prophecy angle might work in benefit of the film, again the Prophecy is never mentioned in the OT. It would even make Vader's sacrifice more powerful.
Last, here's a short clip adressing both issues: