Sarcasm is an adjusted stress reaction.

Aang not being a perfect dad seemed totally in character to me - obviously he loved Kya and Bumi, and they wanted his attention and were jealous when it shifted to Tenzin, but it makes perfect sense to me that once he had another airbender to train, that was going to take all his attention. I think it slots neatly into Aang's character flaws and blindspots.

I just wished Korra were a little less angry at her dad and a lot more angry at a bunch of soldiers who were going to launch an attack on some kids. I thought that made her look ...not very bright, to be charitable.