Episodes VII-IX: The White Page
Most of this must remain untold for the moment, for fear of spoilers.
Yet I think I can guess some of what was originally intended here.
The children of Leia Organa, and of Han and Mina, would be the principal protagonists, along with the fully-grown Mace Windom.
Oeeta Kadar would at last come into the tale in her own right, and would find a suitable husband.
The continued existence in exile of the Pestage dynasty on Alderaan, and its connections with the Republic’s conservative nobility, would bear bitter fruit.
Space Oddities would be important.
Dagobah would be seen on screen at last.
The chronology of the three films, taken together, would be extremely unusual, and rather un-filmic.
Annikin Starkiller’s cursed Lone Ring would at last be destroyed—in an unexpected fashion.
And, perhaps, one might also expect to see early versions of Jacen and Jaina Solo… and even, just maybe, of Darth Caedus.
PS:
Episodes x-xii: Three Days in the Lives
Not much to see here. The remaining three episodes of the “12-film plan” (if ever there was such a coherent plan) were likely going to be three “day in the life” stories, about ordinary folk in the SW galaxy.
Most probably, the films would have concerned Wookiees, droids, and bounty hunters.
(After all, where is Boba Fett in the above outline?!?)