Avatar The Last Airbender
was about a group of kids and teens who traveled the world, going from place to place and not stopping for long, in an attempt to end a war started by an obvious villain with a standard "take over the world" goal. It was set in a world of Asian mythology similar to society a few hundred years ago.
The sequel makes it clear early on that it is a very different cartoon providing a very different experience. Korra is not a kid who hangs out with kid friends; she is a teenager, and a very headstrong one. In fact, characterization is one thing I feel is very well done in this show, as Korra is believable with her mixture of flaws and virtues. She wants to do the right thing, but is reckless and impulsive and impatient. She feels like a real human being.
The world is very different from the previous show, to the point where I can say it's a different genre. Technology that is largely 20th century exists alongside the "bending" magic of the original show, so we can see how people who can manipulate earth, air, water and fire would live in a society similar to ours, where cars, radio and pro wrestling - I mean, pro bending - tournaments all exist. We are shown the things that everyday people do, the things they do for fun and the things they care about.
And speaking of things they care about, we are soon introduced to a very vocal anti-bending faction that feels discriminated against by the benders. Korra of course is quick to protest this despite not being familiar with the situation and being new to Republic City, but it isn't long before she witnesses a gang of benders extorting money from a non-bender, and we see what the anti-bending faction is upset about.
Which leads me to my next point. Even though only the first two episodes have been released thus far as a special promotion, it already looks like this show will deal with more complex nuances than "Big Bad
wants to take over world, stop him!" Themes of discrimination, prejudice and distrust, and even good ideas gone horribly wrong already appear early on. With the show set in one location, there's room for far more character development, and we will likely see how Republic City itself changes over time.
So far, a great showing for a very different sequel.