Thanks for the kind words, folks.
As for a book on Braavos? I truthfully don't know. With several books that include a pretty significant chunk of narrative set on the Wall, there was a goodly amount to go on in describing not just the Wall, but the wildlings beyond it. As a developer, I'm honestly not sure if we have enough narrative describing what Braavos is like.
The Night's Watch book is, indeed, a good example of our philosophy of dealing with the dilemma of describing a setting that we don't have creative control over. It's a balancing act, but one that I think we did a pretty solid job of.
All of the books of our line go to Mr. Martin's folks for review and approvals. If he sees things that need changing, then we make those changes before they see print.