I only saw part of Korra and what I saw was okay - life got busy and I didn't keep up, then I never had a chance to go back to it. I did hear about a lot of stuff going on behind the scenes, but I'm not up on the details. If you do watch it, my recommendation would be to approach it as it's own separate entity rather than as a sequel. It's very different from the original.

But I'm really glad AtLA lived up to the hype for you. :)