Those are good thoughts -I love that McQuarrie stuff!
A thought I had on my own was that an approach of this kind might best be done telling the prequel story from Obi Wan's point of view. That's another idea I haven't heard before.
TPM would shrink considerably if it were recut to seem as if it were his story. But it actually sounds like an interesting way to shrink it, imho. So many sequences would have to be off-screen, but little that matters, since trying to make young Vader "likable" wouldn't be a concern.
It would probably mean cutting the prequels to rwo or even one movie.
That would be best-- Two movies, STAR WARS and one Prequel.
Hmmm...