Not the same guy, but I started reading it a few weeks ago and just finished the fourth book last night. It does a pretty good job at both world building and character development in my opinion (though it really shines across books). In my opinion, the first book does a good job of introducing new elements of the setting at a good pace, and uses it’s characters who know little of the world to impart how special/rare some of the things are.
The exact one that came to my mind. It’s wild that the totally legitimate movement just died overnight because their leader was revealed to be a bender. I know they mentioned the government reforms to appease non benders, and realistically the show just wanted to move on, but it definitely still sticks out to me over a decade later