Hickory: Have you actually read it? It completely splits from the video game's storyline from the very first page: the protagonist, Abdel Adrian, is a Sellsword who actually left Candlekeep years ago, and is widely travelled (Baldur's Gate, Athkatla -- he was a warehouse guard in Athkatla!); Imoen (like many other characters) is non-existant; Gorion is killed by random mercs, unconnected to Sarevok; Sarevok is unaware of protagonist until the last of the mercs fall to him; Tamoko is Sarevok's sex slave come assassin; Xzar and Montaron work for Sarevok... I'm not even going to continue. It's a complete farce.
Edit: oh, and the salt in the wound is that WotC actually adopted such trash as 'canon'.
Never read it, and don't plan on it. I can get making up a backstory for the main character that doesn't quite match up with the one in the game, since the general lack of detail on the origin seems to have been done to allow the player to come up with that on their own; problem is that the protagonist can't have been outside of Candlekeep, since his heritage is why he was brought to Gorion as a child, in an attempt to keep him safe and maybe have him turn out to be a halfway decent person. Having him have a life in the city prior to Candlekeep just begs the question of why Sarevok didn't kill him as well, aside from the plot convenience fairy waving her wand.
Changing some of the characters to give them more involvement in the plot I can also get, at least theoretically. I mean, the NPCs as it stand don't really do all that much beyond follow the PC around aside from a few that come with a minor sidequest attached. Characters with that level of inactivity just wouldn't work in a book, so some change is understandable. Having Xzar and Montaron being retconned into double agents for the Iron Throne who are pretending to be Zhents (or just scrapping the whole Zhent angle altogether) could give them a way to have some connection to the main plot outside of being just two random dudes the protagonist meets. Hell, they could have become minor villains in their own right if the writer put their mind to it.
Killing Gorion off by random thugs is pointless as hell, though. Actually, it's more than pointless, it's actively harmful to the narrative. In the game, his death serves to reveal to the PC that Sarevok is after them and is a threat able to take on the likes of Gorion; killing him with random mercs doesn't do anything to establish the main conflict at all.
Actually, the more I think about it, I might be tempted to pick this up, if only to do an MST3K style running critque on Goodreads. I mean, it's not like it could be any worse than Dracula: the Undead.