Royal Assassin is the second book in The Farseer Trilogy. It is the second book of a trilogy, which is all that needs to be said of it, unfortunately. It is well written. It advances the plot well enough. Unfortunately, it suffers from the condition of being the second book in a trilogy with the author is sure that there will be a third. By which, I mean that it is not a book on its own, but more of a setup for the third. The first book has to stand on its own, since there is no guarantee that the author will ever get a shot at any other books. The third one does too, to some degree. The author cannot depend on the reader to have read the previous books (doing otherwise would mean that the book would not be able to get more readers than the previous installment, a bad state of affairs). The third book is also responsible for wrapping up the plot since it is the end of the trilogy. That leaves the second book in the trilogy.
The second book has just enough of an introduction to the setting for the reader to be able to understand the motivations of characters. It then proceeds to start advancing the characters from the first book and setting up plot threads for the third book... and then it stops. It has to resolution. It has no conclusion. It is the author reaching a page count that she feels is sufficient to sell it as a full novel, reaches a point where the reader can stop for a bit and still pick up the book later, and puts in a “To be concluded in the next book.”
The author is under no obligation to give any of the plot threads and closure or conclusion. It is likely better for the author that she did not since it leaves the reader that much more tempted to keep reading the series. It is sufferable if one has the third book already or expects to read it in reasonable time. It also leaves one feeling cheated. The reader has taken the time to read the book and yet is left with a story that is unfinished. It feels like the book is nothing more than a marketing ploy for the third book. It is as if the author left it unfinished to force the reader to finish reading the series or face a situation when the effort of reading the second book was for naught. I suspect that it is not the case and it is just that the author had crafted a plot that requires multiple books to convey and did not take the effort to separate it into self-contained installments.
As I was coming to this opinion, I thought to find examples of trilogies that did not fall into the same pattern of a middle book that does not stand on its own, and I found many series that did not suffer thus, but I also found that many successful plots do have the same problem. Look at the original Star Wars films for example: A New Hope does a magnificent job of introducing characters, establishing the motivations of the major factions, creating a plot that draws the viewer in, and coming to a satisfying --- if not finalizing --- conclusion. Return of the Jedi takes all the plots and conflicts from the previous two films and brings them together on a single battle field to have then resolved totally and decisively. The Empire Strikes Back is a magnificent film; unfortunately it does not have much of a conclusion: Han is on his way to Jabba so he can be rescued in the beginning of the next film, Luke’s training is not yet completed, and the movie drops its biggest surprise --- the relationship between Luke and Vader --- in the last moments of the third act leaving the implications unexplored.
Royal Assassin is very much the same; it advances the plot significantly and sets up a great deal of conflict, but leaves the user unsatisfied. The ending is just a point where the protagonist is out of immediate mortal danger, but the state of the plot is completely unresolved. Too many of the plot threads that the books sets up are left unexplored, left for the third book to pull together.