Lord Lucien
Lets all love Lain
Again, just because it technically was expanded, doesn't mean it was good. Hence my metaphor. The only thing you listed there that I'd call genuinely interesting is the HINT of a Sith lore. They didn't really tell us anything about the Sith, just sorta said that they exist. It was left to the EU to flesh them out better.
Same with everything you said, actually (except the Banking Clan, because nobody except weird diehards care about that). The PT introduced them, but nothing else. It's a sign of a bad film if it's own story and world is so underdeveloped, lackluster, and empty that it requires additional ancillary material to bring any life or sense into it. The PT-era EU was generally pretty good, and I'd put that down to there being so little of anything of substance in the actual films that the EU had nowhere to go but up. In contrast, I've always found the EU material centred around the OT characters to be very tedious and cringy--like the writers were trying but not quite succeeding at capturing the feel of those movies and its characters.
Which brings me my back around to my central point: I wish the Star Wars universe and franchise had ended with RotJ in 1983. And instead of trying to rewrite, resurrect, re-hash, or re-imagine the initial films from decades ago, that consumers and producers of fiction had created something new and different. Instead of endless Star Wars.