I know that people really had issues with book 1 but I really liked Katara , Toph is my second then Azula/Mai , and Last would be Korra except that the Love rout for Korra certainly made me like her a bit more if I was going on the Slave rout Korra I hated her.
Book 1 certainly had pacing issues and repetitive issues and if I had stopped playing the game right after my feeling for katara would not be as strong. Her re-appearance in Book 3 is probably clouding my over all opinion about my best girl. From a strictly game play perspective book three was more fun, book 2 comes in second and then book 4 followed by book one. either slave or Love does not really change the game play aspect to me.
I guess I will have to look at Toph's face in the two routs did not notice a difference but then I played the game all the way through in one rout or the other so it was a fair amount of time between me seeing the two faces of Toph.
Edit a Typo.