Darksaber is probably conceptually KJA's worst novel of his four "adult novels," IMO. I think if you look at his plots he shows that he's very much in the same storytelling vein as Lucas with ROTJ and TPM in that he likes to juggle a lot of plotlines; with Darksaber you have the Callista plotline which seems to be the reason why the book exists, to get her out of the picture, then you've got the Daala plotline and the Durga plotline that gives the book its title. I haven't inflicted Darksaber on myself in several years but I don't think that the Darksaber storyline has any overlap with the other two, except I guess superficially at the beginning when Luke and Han go on Tatooine so that KJA can reuse material from his The Illustrated Guide to the Star Wars Universe with them riding along with Tusken Raiders in a scene that doesn't do anything to advance the plot, but they're there investigating Jabba's palace because the Hutts were snooping around there because Jabba had codes to Coruscant computers or something and the New Republic keeps the Death Star plans lying around because they might forget to target the exhaust port if someone built the Death Star from the plans they leave lying around, and Bevel Lemelisk needed the Death Star plans to build the superlaser for some reason. But then Luke and Han were also there to ask Obi-Wan for help at his hut, because Luke talked to him there before, and not anywhere else. As I recall, the last time I re-read the novel I found Leia's "diplomating" to be embarrassing for both KJA and me to read.