I kind of knew something about Fett, but I think his background draws from the EU, so I'll have to pass :D

Well, no one actually hates ROTJ, but most of the people I know (including myself) think it's an "half-assed" movie :D It looks 50% Star Wars (with Luke's journey to the Emperor) and 50% something else (with childish or lifeless characters, a good amount of bad special effects and an odd pacing), and when it comes to retcons, ROTJ is the one starting the "shrinking galaxy" trend, with Leia being Luke's sister which, compared to Vader's revelation which draws a parallel within the protagonist and TESB's main villain, is just here to fix a plot hole and has no actual impact on the story (aside for Vader's threat to make her into a dark jedi).

Speaking of ANH's drafts, it's common for stories to have multiple versions until a final polished one is written. The reason it took so long for ANH, is that it initially drew from a lot of sources (sci-fi novels, contemporary society and Lucas's own experience) which made the script very confusing, so it had to be streamlined more and more until it became what we know today.