One thing everybody seems to have a problem with is that Legend of Korra is not The Last Airbender. Guess what? That's the whole freaking point! The one thing you cannot accuse it of being is just a rehash of stuff done by it's predecessor. That's a good place to start a sequel. Now, have they succeeded? No, not entirely. But at least it has the guts to try. And when it works, it reall works. Think about Beginnings being absolutely fantastic episodes. Or taking half an episode to tell the back story of the villains, in the second to last episode. That is where the true genius of the writers shines through. For a lot of stuff that doesn't work, I'm kind of inclined to blame Nickelodeon.
Here's a bit of the story of the conception of these shows: Konietzko and DiMartino spent 4 years thinking of and writing The Last Airbender, before he first episode aired. They then had another year for each following season. The decision to finally go with Legend of Korra was made in late 2009, after Nick first declined the stories that would ultimately be turned into The Promise and The Search. Then Nick complained they didn't want a female protaganist, but ultimately gave in and said they could do one season. After it was announced in 2010, the split between the fans began. On the one hand, the people who thought ''Iceberg right ahead, Prequels all over again'' and the people who were generally excited to see the show coming back. So in 2011 Nick told the creators of the show to also do a second season, when the animation of the first season was already halfway done. Shortly after, they started negociating again afterwards, Nick also agreed to two more seasons after that. So in short: there were 4 years between the first ideas and the initial airing of The Last Airbender, 3 years for the first season Legend of Korra, only 2 for the second season and 3 for the current season.
Hell, the reason Beginnings is so good is because it had been written when Konietzko and DiMartino were writing season 2 of The Last Airbender. They ultimately deemed it too difficult to fit into the existing storyline and shelved the concepts. Instead they wrote the episode ''The Avatar State'', explaining how it works, but not where it came from. Because they were running low on time for season 2 Legend of Korra, they pulled it out again, and with minor modifications managed to work it into the story.
So the title ''Avatar but still Korra'' is something we're meant to take as an insult, but I actually think that's a great thing. It's not like The Last Airbender because it's not trying to be and the start of season 3 really captures that for me. It has the nature of its great predecessor but is very much doing its own thing. It's going for a slow, character focused build up, unlike season 2, which just just throws a ton of stuff at you and then grinds to a halt. (Or as Rob Walker said: throws everything at the wall and hope it sticks, but is completely shatters) It actually has me legitimately excited again, and not just; ''Well, if I have to choose between watching Avatar or Transformers...'' I think this is a great show, taking bold risks and by far the best Nickleodeon show currenly running. Hell, it's much better than a talking sponge voiced by Wheelie from Transformers 2.