Loved the original (Seen it several times), but I could only watch the first few episodes of Korra.
Aside from the society going from a nice Eastern style Buddhist to an industrial city, FatherXmas is right, it lacks things to lighten the mood. I didn't see the humour.
Different style in writing, different environment, basically a whole different world. Even the police using metal bending doesn't seem right, I thought only a couple of the strongest earth benders in the world could do that after finding enlightenment that the elements are connected and metal is just refined earth. It seems it went from a spiritual journey, realizing the philosophies of the Air nomads, exploring the vast history of the nations...to a teenage girl with problems.
I would say Avatar was much more holistic in it's lore, character and world, and unfortunately Korra is stuck in a world where that's had it's history already restored.
That being said, in the last Avatar episode we see Aang learning that originally they would bend energy before the elements. You could explore that a bit more.
Honestly I think they should have gone backwards. Go back to a PREVIOUS Avatar, make things even more simple (Less tech) but have the same problems/challenges. I would most likely watch that.
Bending elements in a society without technology > Bending elements when cars exist