Try and keep it clean, folks...
The original, and very vague, outlines for Episodes 7-9 would have taken place in a series which did NOT end with Episode VI. That ending was not the original plan. Originally the final confrontation with the Emperor would have taken place in Episode IX and likely ended the same way we saw it.
The trilogy would have been about Luke graduating from trainee to proper Knight, and looking for his sister, who would not have been Leia.
But once GL wrote ROTJ as the conclusion to the story, the whole of this vague outline became irrelevant.