Now that we are getting the OTR on DVD, I really don't care what Mr. Insano (aka George Lucas) does to the films, and I think that some of your changes sound OK if you wanted a 6 part saga that works. Personally I think the best way would have been to make prequels that matched and did't contradict the originals, but hey. From a hypothetical standpoint I don't see any problem with Je's ideas. But replacing Alec Guinness?

BTW you might like to check out the Starkiller Ranch thread in the preservations section - they are working on edits of all six movies so that they work better as a saga.