
Yeah, they stick pretty close to the book in the first one, but there's definitely stuff missing. I really would have liked to explain where those dogs at the end come from a little better, I thought that was a really sinister and intersting surprise in the book, but in the movie they're just bad-CGI dogs.
And Korra gets way worse in the second season, yes. I didn't put any spoilers in my review of the second season in this blog if you want to know how.