Book 1 - Wind of Legend of Korra ended with a sugar coated ending, in which nothing is left to solve anymore. Korra regained her power, got the connection to her previous incarnations, Mako choose her and the antagonist Amon is probably dead.
So the question is what is left for Korra and her gang to do in the next season? The Short Answer would be: A lot! The longer one follows:
<--- Preview Sketch by moxie2D
The end was as i previously said kinda rushed and the only bitter part of the great experience the series delivered. The kinda death of Amon will most likely revoked further in the story, which i really really hope they don't. Besides, there are a lot more things to archieve than master the 4 elements. Korra will improve her ability to get into the spirit world and who knows what for horrific disasters she will learn there regarding the future of the world. The only thing we now know is that the second season ist called Spirits and will be aired sometime in 2013. There will be another 2 books afterwards, combining them to a whole 52 episode epic series. Great!
I can't wait till the next seasons start and hope that it will never ends. Its just to good for that and somehow i fear that if Korra ends, then there won't be another successor.
Here are the full ComiCon panel with the creators answering fan questions: