while I will give that arthas adheres far too much to information found in WC3... it still gives a lot of insight into arthas's fall and his relationship with jaina. The horse is clearly key to his personality... Hardly anything to hold against the book.

As far as I have been able to tell... there isn't any lore that doesn't match up in the novels. The authors have been pretty good about not screwing stuff up like that. Especially considering only two authors wrote the bulk of the books - Richard Knaak and Christie Golden.