Having looked over the scripts and drafts of A New Hope it is clear that many of the ideas George initally had were either shifted around, were removed from the story or removed because it was technologically impossible at the time. Given the pure mythic and 'fariy-tale-esc' vibe to those scripts to what extent would it be possible to adapt them into new Star Wars films set within a different era without it being a re-hash of the original film? In this way a new 'monomythic' hero would be established within the same universe yet set in a different era. Given the information we have from the films and television series' I think it would be a cool project to try and adapt the scripts into a new era.
This think the 'Story Synopsis' from 1973 could also be adapted:
http://starwarz.com/starkiller/2010/03/the-star-wars-story-synopsis/
Firstly if you adapt it to a new era it could work quite well. The impression I get from these scripts seems very Far Eastern, with the landscape and setting of a mythic China or Tibet - this was very much the overall vibe of Ralph McQuarrie's art also. If you were to put this around 10,000 BBY in the timeline, give it a distinctly removed atmosphere from the Saga (like a true "Star Wars" period film), and create a scenario were the Sith wars are continuing and the planet on which this occurs is in occupied territory then I think it is far enough removed from A New Hope.
You could develop the scenario, which I would have implemented with the Prequels, that the Jedi are spread throughout the galaxy like wizards, keeping peace and justice - it could be reasoned that the Jedi had a different structure in the past. In this case the General - who is Luke in the synopsis - is an old Jedi whose planet has been occupied by an evil Empire governed by the Sith (not a purely 'Sith Empire' just an Empire where the Sith are like the Imperial Guard or Aristocracy). The movie could then progress as per the synopsis, implementing many of Ralph McQuarrie's style in the overall atmosphere of the peice.
http://artect.net/wp-content/uploads/2007/11/mcquarriestarwars03.jpg
http://30.media.tumblr.com/tumblr_l5f7u6DjsN1qc823io1_500.jpg
http://www.theforce.net/episode2/newspics/rmq-coruscant3.jpg
http://www.theforce.net/episode2/newspics/rmq-coruscant4.jpg
http://www.loresdelsith.net/universo/galaxia/bin/monumentpark.jpg
This would take the Saga back to its mythic routes. It would be partcially a reboot of the franchise only set within another era and would be compatible with the current Saga. Other areas of myth and legend could be explored and the Darth Vader-type character could be another tragic yet unrelated figure to the characters.
A sequel or trilogy could then be developed of the General and his band taking the fight to the 'Sith' Empire which takes them to the heart of the Republic; Coruscant and Alderaan.
Furthermore, in order for the trilogy to not falter from the whole oh-well-we-know-what-happens-ten-thousand-years-later, some philosophical talk could be introduced by the aged General to the main protagonist. Simply put; although evil may return what matters is that peace has been given to your time and that others will travel your journey again to once again stop evil - perhaps even stop it once and for all.