Actually I posted a response to that article you linked describing this book and your map - but it's still awaiting moderation before it's posted. My post to that article regards the "river issues in your map". (Note: I am a member of the River Police - look beneath my avatar name).
The river system to the west side of your map has a general north to south flow, however, several of the tributaries seem to be flowing backwards and merge with the main river from the wrong direction - I see a half dozen examples of backwards pointing tributaries on that river system. Also, though large rivers can form deltas as the river nears the sea, your delta seems expansively large, almost too large - the rivers are splitting away from the coast too far away from the coast, though this is still possible, so I'm not trying to be overly critical.
Of the river system to the east, there's a similar too big a delta situation here as well, but more critical you have a river reaching the sea significantly north of the 2 rivers of the delta. If this were the case the entire river would flow into the sea at this point and not continue southward to split into 2 more rivers reaching the sea. Generally except in river deltas, a river can only reach the sea at one exit.
A river delta occurs when the land near the coast is extremely flat, the river slows down it's pace and detritus in the water begins to settle on the river floor building up and eventually pushing the river to one side or the other starting another channel. This is what causes multiple channels to appear in a river delta.
Since your map has been accepted by the author and publisher, there probably isn't a need to fix the rivers for publication, but for geologic/geographic authenticity you should use correct river formations in any published map. Unless the author is specifically ruling that the storyline requires unrealistic geographic formations, there should be no reason not to get the rivers correct.
We've got several threads in this forum discussing issues with river systems, as "rivers" of all geologic formations seems to be the one that most often have problems with inexperienced cartographers.
Aside from the river issues, though, this is a pretty map!