Well, i really didn't like first season(i wacthed till the end, oh god ... the end...) and so far the most interessing thing is about tenzin and his family. I really dislike korra now. She did the exactaly same mistake that she made first season (trust the first fellow that says: hey, come battle with me), but yet nobody tried to tell her about this.
And, quoting a ign comenter:
"But everything changed when the North tribe attacked"
"Hardware design isn’t about making the most powerful thing you can.
Today most hardware design is left to other companies, but when you make hardware without taking into account the needs of the eventual software developers, you end up with bloated hardware full of pointless excess. From the outset one must consider design from both a hardware and software perspective."
Gunpei Yoko