World Expanding with the Walking Dead Novels

Both The Walking Dead television show and the comic book series are incredibly popular, sharing similarities but so different in story and character arc that they constitute separate universes. Less well known (relatively) is the series of novels, written initially by Robert Kirkman with Jay Bonansinga, and later taken over by Bonansinga as the sole writer. These novels, set in the comic universe, explore the rise of the Governor in more depth, and then follow events in Woodbury after he is gone. What ways do the novels expand the world of the comics, in terms of character and plot development, and how does the post-governor Woodbury relate to other types of societies seen in the series?