As excellent as I already think this movie was on its own, I think it becomes an even BETTER movie when viewed in context of the entire trilogy.
Consider things that would improve the continuity of Ep IV. Writing the character of the Emperor in (you would think he would at least come up in conversation at some point), establishing what the hierarchy was between Vader and the Imperial commanders, introducing the Rebellion leaders (Ackbar, etc.), foreshadowing relationships, giving an actual motivation for blowing up an entire damn planet, etc. Some of this information wouldn't have made any sense prior to the completion of the trilogy. But Ep IV was a standalone movie, and George had no idea where he was going from there.
Episode VIII is going to have a ton of "OOOOOH that's why _______ happened" moments.
Consider things that would improve the continuity of Ep IV. Writing the character of the Emperor in (you would think he would at least come up in conversation at some point), establishing what the hierarchy was between Vader and the Imperial commanders, introducing the Rebellion leaders (Ackbar, etc.), foreshadowing relationships, giving an actual motivation for blowing up an entire damn planet, etc. Some of this information wouldn't have made any sense prior to the completion of the trilogy. But Ep IV was a standalone movie, and George had no idea where he was going from there.
Episode VIII is going to have a ton of "OOOOOH that's why _______ happened" moments.