Not to mention the romantic tension between Luke and Leia.
I'm kind of surprised to see that angle get downplayed here; in other discussions I've read, it's been one of the main points and used as proof that Lucas was just making this stuff up as he went along. (I doubt he had as much control over SW back then as he later got, but I'd be surprised if there's anything significant in Splinter that he didn't sign off on.)
I just read the 3rd or 4th edition of RotJ, and even that was significantly different then the movie. I hear the subsequent editions had been modified to reflect the movie more closely.
But it was much darker too. Suggestions of Leia being raped by Jabba being the foremost. Issues around Ben and Luke. I liked it, but it certainly punctuates that Lucas's claims of having this whole space opera mapped out from the get-go, is pure BS.
Oh, yeah. There's simply no way the original trilogy was planned as the second half of Darth Vader's life story, and there was obviously a lot of second guessing going on between SW, TESB, and ROTJ.
It's hard to remember a time when the first movie, this book, and a handful of comics were the totality of Star Wars.
Not for me, but 50 isn't too far away and 40's way back in the distance in the rearview. Hell, I remember when Heir to the Empire showed up in bookstores with a special wraparound banner pointing out that it was on sale for a special introductory low price. Still have mine, though I never got around to the other books in the trilogy.
Just think... for a decade or so, the only original SW novels were Splinter, Brian Daley's Han Solo trilogy, and L. Neil Smith's Lando Calrissian trilogy.