I was looking through recent blog posts and I saw one with a similar title to mine, except that one was only 1 sentence long and it simply asked users what their predictions were. Well, rather than writing this in a comment I decided to write them here:
Main Plot Edit
- Since Book 2 is still technically in the first season, it would make sense to believe that the two plots are closely related.
- I believe the Equalists will still be around (if not all, some). How likely is it that they'd stop hating benders after Amon died?
- Hiroshi Sato will be the Equalists' new leader.
- Team Avatar will visit the Fire Nation and accouter the Fire Lord (Zuko's daughter) and Zuko
- Zuko's wife will be Suki. (Read The Promise, Part 2. It is possible)
- It will be revealed that Sokka ended up with Toph. (Again, read The Promise, Part 2.)
- Lieutenant will become an important ally.
- Asami will ultimately be the one to bring down her father.
- We'll see a Patik-esque character help Korra out with Avatar State.
- Korra will speak with Roku, Kyoshi, and Kuruk.
- Asami will be so focused on her dad, she won't worry about Mako.
- Another girl we don't know yet will meet Bolin.
- Lin and Tenzin will grow closer together (I'm calling for Pema's death in Book 4, seriously)
- Korra and Mako will go through difficulties, but unfortunately, everything will be super perfect by the end of the book just like Book 1.
Other Things Edit
- Katara will die.
- Korra will master Airbending (kinda obvious)
- Tenzin will become the Council's chairman