4 episodes in and I think I'm already liking this season better than the last. I think getting out of the city helped. It took a while to get straightened out which tribe was the southern one and which was the north and how that related to what we saw in Avatar, but once I did, everything began to fall into place. I like that we're spending so much time with the water tribes since, in the previous series, we only had three episodes set aside for them (well, plus the one for the bloodbender chick). Chief Unalaq should make for a good antagonist.
Loved the focus on Aang's kids and grandkids in the B story.
I even enjoyed the C story, with Bolin helping Asami with her business deal with Varrick. Everything about hiding in the stuffed platypus bear was amazing. The thing with him and Korra's weird cousin, however, came about way too suddenly and felt really forced. The dynamic could have worked, but it should have built up more over the course of the season.
That said, I want Lin back in the cast.