You know what's pretty awful?
Although I must admit I haven't read many of them, but the few official Star Trek novels I read were all glorified fanfiction, every one of them had clear self-inserts, this random lieutenant that wasn't on the show but is suspiciously friendly with the senior staff. Plus they have to have their favorite characters in all of their book. Data showed up in so many of these books, here's the catch; I DIDN'T READ A SINGLE TNG NOVEL.
Two of the very worst I've read for example, first the Voyager Relaunch novel. That deals with what happens when they got back. The TV show gave us nothing except fake closure. So finally get to see what happens!!
... Yeah well, awful garbage happens. Holograms trying to have a revolt, while Star Fleet intelligence goes lock down on all Voyager personnel. And a plot about the head of Star Fleet intelligence trying to turn herself into a new Borg Queen (Which was apparently abused/raped by her step father. You know, something that would make Gene spin in his grave. We find that thanks to random segment about "The hand" that feel so out of place in a Star Trek novel)
Of course they need Data's because of The Value of a Man. Oh and the author wrote "Picard's hazel eyes" ... HAZEL?
And then, this one really fucking broke my heart, but "A Stitch in Time" co-written by Andrew Robinson himself, Garak's memoires of his early days and time at the obsidian order. Sounds like the best thing you could ask for. But it was dry, so dry, and shows Garak too much like he was on the show and not as anything else. Plus has this whole tale about how he was hiding in the sand for some excersize and befriended some sand creature he called Mila. It was bad, it was dumb, it made the Obsidian order seem like a joke and I could never bring myself to finish it.
I think the only novel is vaguely enjoyed was huuh, Unity of Duty? I forget but it was about Rougal, that young Cardassian orphan that was raised by Bajorans until he's eventually reunited with his father and returned to Cardassia. It's cool because it basically shows the entirely of the events of the DS9 timeline but as seen from the perspective of the Cardassians. Rougal ends up being coerced into military service by Dukat (Because gotta shoehorn the cool chars) and does get out of the Dominion war alive, but certainly a changed man.
Anyone read anything decent?