I remember watching Korra. I saw the entire series from beginning to end. It was originally meant to last only one season, which is why season 1 felt rushed. But it was so popular and did so well that they decided to keep it going... And I'll just say that it shows in the first half of season 2.
But yeah, I pretty much agree with you about Korra. It had its flaws and is not on the same level as the original, but it's still a damn good show overall.
It did look really nice now that you mention it, and I also remember it sounding awesome on my HT. I'll be honest, I don't really remember a lot of stuff from it aside from some key moments, but I'm guessing "Beginnings" is that one episode with the first avatar and stuff? Cause if so, that was definitely one of the highlights of the show for me.
*Korra spoilers* (I really hated when Korra broke the connection to previous avatars later on though).