The recap for episode 2, "A Leaf in the Wind" is now live, wherein I find something that looks suspiciously like a unifying theme for the past 2 episodes and possibly the whole season. Some of the content in there also owes a bit to Neo Yi's review earlier where she pointed out how Tenzin and Korra's resolution manages to show that they're both wrong without making either one Wrong.
One thing that didn't make it in was the fact that a character's age is no indication on which side they'll end up on in the Old vs. New divide. Katara is one of the oldest characters we've seen so far, but she's squarely on the "New" side when she tells Korra to go seek out her own destiny, against Tenzin's wishes. Korra is one of the youngest characters, but she comes off as an old-world throwback with her tribal garb and national colors in comparison to everyone who's not Tenzin in Republic City. The only plot point that doesn't look like it'll be covered by the Old vs. New theme would be the angsty teen romance stuff between Korra and Mako (they can't stand each other...of course they're going to end up together).