If Lucas had wanted to keep the surprises of the movies when watched in sequence then Yoda could only be mentioned, not seen, and Anakin turning into Darth Vader couldnt be shown.

I saw ESB in 1980 and the surprises were the highlight of the movie--I expected Yoda to be some austere bearded guy on a throne in the swamp and the Vader revelation was a real shocker.

Anything was possible--Darth Vader could have been around from the start of the movie (wouldnt that have been a surprise?) and Anakin Skywalker fights Vader before Obi Wan and Vader gets severely wounded or seemingly killed..and then after Anakin's defeat we see Darth Vader reappear(him having taken the name and persona of the character after the Emperor fixes him up). I hated the Prequels--so any change is ok with me. lol

And I also expected that General Kenobi would have been out of the jedi order and some kind of mercenary wandering Jedi fellow when he encounters Anakin. He did say in SW he didnt go by the name of Obi Wan for a long time...

And I expected Luke to be on Dagobah as an infant..