^Don't worry, I'm certain that sooner or later, Korra will go on a spirit journey and meet Ang. So there's that at least.
Maybe it's just the story being restricted to one city, the implied shadowy conspiracies or the anthology style narrative, but the tone of the show reminds me a lot of the latter half of 'Book Two: Earth'. Which suits me fine since the Ba Sing Se arc is still my favourite part of the old show.
As for what the core conflict actually is, I read somewhere that it has something to do with Zuko, or his legacy. Not sure if that's political--Republic City is build where the old fire nation colonies were--familial like an heir or pretender or something more personal, perhaps tied to his Blue Spirit alter ego.