That's a hell of a project and would be pretty cool, like the Revenge of the Sith teaser's flashback to the PT, which was excellent, I tell you.
It'd probably be really cool. The only thing standing against it might be the secret to immortality being fumbled and left unresolved in Sith. We know that yoda, obiwan, quigon, and Anakin ultimately reach oneness with the force, but not a hair of how they do it. And that's an issue it seems lucas will take with him to the grave unless he has more changes in store for ep 3.
As an addition to what you've already mentioned, how about inserting a quick flashback to Obiwan on the "high ground" when we see Luke flip up to that walkway away from Vader. Then it'll be somewhat of a surprise to see Vader just chuck his saber at Luke rather than jump up there to lose his limbs again. No, I'm not being serious.