There's an unfortunate tendency within the fantasy genre for books to decline in quality as a series progresses. I'm certainly not pegging this to any difference between the talents of writers in general and the talents of fantasy authors; since fantasy is a genre overpopulated with series compared to some others, it's hard to know how much of the typical decline is attributable to aggregate author ability and how much to the inherent weakness of the series format: you can't always find that much to say, long-term, about a given set of characters*.
Lynn Flewelling disappointed me, although she did not overly surprise me, with the poor quality of The White Road, the fifth book in a series she began in 1996 with Luck in the Shadows. The Nightrunner series follows Seregil and Alec, pseudo-nobles (in a socioeconomic rather than moral sense) who steal, spy, and mix themselves up in whatever political intrigue happens to be going at the time. Two people, both of whom have shared household accommodations with me at different times, independently read this series, both of them when they were bored and raided my bulging bookshelves out of desperation. Both of them, independently, began referring to the series as "the gay thieves."
This is more than a coincidence. While the first couple of books have quite a bit more going on than that, the characters' identities as gay thieves are pretty central to the plot and to the character development, to use an only marginally applicable term. As the series progresses, the fact that the thieves are in fact gay becomes overwhelmingly important to the plots and themes of the books. Just as a series of books focusing on how a pair of heterosexual lovers like to have sex with each other and potentially with other heterosexuals would become incredibly dull after a while, so does the Nightrunner series become monotonous, if not at all times strictly monogamous.
My reaction to the first two books could be summed up as: Cool. I like reading books about thieves** and assassins. (Full disclosure of personal bias: I always play the rogue character class in any given RPG video game.) These books are at least of average quality, which qualifies as an Epic Win (to make a bad pun, given the usual sweeping plots in fantasy novels) given the crud available at the bookstore.
My reaction to the third book: Okay. That was okay.
The fourth book: I effing get it. They're gay. And they're thieves sometimes, too, but mostly they're gay. Gay! Got it.
And by the time we get to the fifth book, The White Road, the quality of the actual writing had declined sufficiently that even a much stronger plot, and a much decreased focus on the overwhelming tendencies of the main characters to have gay sex, frequently, would not have saved this book from being not quite worth the time or the $7.99 cover price. I think this writing quality issue may have a lot to do with a pre-built audience; a certain proportion of those who bought the first four books were counted on by the publisher to buy the fifth book no matter what, and the onus of luring new readers pretty much remained on the first book, which is much better.
Even so, there's no excuse for sloppiness. One might even say that there's less excuse for sloppiness when, as in the case of The White Road, it's possible that the sloppiness was calculated to some degree.
Overall lesson to be learned from this book: Unless you are writing erotica, the sexual orientation of your characters will not carry a story. Homosexuality can certainly be an interesting addition to a fantasy's complexity, but it can also become just another gimmick to set a book apart from otherwise comparable books without any homosexual relationships.
The White Road gets two stars within its genre***.
* There are exceptions on all sides of this question. Whatever your opinion of the Harry Potter series in general, it is very arguably true that book 7 was in fact much better than book 1, with a consistent rise in quality all the way through. The book series begun with Anne of Green Gables offers an opposite perspective: this is a non-fantasy series of 8 books in which quality noticeably declines after book 4, and arguably after book 3.
** Highly recommended example of the thief-fantasy sub-genre, should that be your dish of tea: The Lies of Locke Lamora, by Scott Lynch.
*** For fantasy readers - and while there are books within the fantasy genre which have much to offer readers who don't typically go for fantasy, Flewelling's books are not among them - I do recommend the first two Nightrunner books and also, more strongly, Flewelling's Tamir Triad, which begins with The Bone Doll's Twin.