I'm a very big fan of the series and what M&B did with LTA was short of spectacular, but I don't have the same feeling with Legend of Korra.
There were 5 things that made me absolutely FURIOUS with how the show ended.
1) How could they do that to Amon? Like what the hell? Amon was my favorite thing about the show, and he was the first real villain that was basically untouchable. He was SCARY. Like seriously. I got chills when he came on the screen. He was able to resist bloodbending as well, and that made you go, "WHAT THE F***?!" The backstory to Tarrlok and Noatok was beautiful, and was easily the best thing about the finale, but I was really upset with how Amon turned out. Also, a little airbending made him weaker? And what was up with Korra suddenly learning to airbend like a PRO? Was it because her dear beloved Mako was getting his ass kicked? Didn't like that either.
2) All of the romance was shoved in our faces. Like for real. Korra and Mako had no development and what about Asami? They didn't even officially break up yet, and the way Mako and Korra suddenly became a thing was completely messed up. Kataara and Aang had 3 seasons worth of build up, so many touching moments and a lot of things that made them who they turned out to be. So we'll see where this goes.
3) Korra turned out to be the most talented avatar of all time in what, 10 to 15 seconds? She lost all her bending, learned airbending, got her bending back, got the ability to GIVE people their bending back, and then she got her prince charming in Mako. That's the biggest problem I had. It was way toooo rushed.
4) There was no EPIC battle.
In TLA, all 3 of the finales had amazing battles. You had the Aang badass Avatar State, the Ba Sing Se underground battle, and Ozai vs. Aang and then Azula vs. Zuko. What was here? Like 3 minutes of Korra learning air bending and Amon blood bending? REALLY disappointed.
5) Finally, they have no storylines to go forward with. Like what the hell? Everything with Korra is basically done, as she's found her spiritual side, learning airbending, and then got Mako. Lin gained her bending back as well, which filled up that plot hole. AGGGGGHHGHGHGH, it's just that I'm so damn frustrated it's not even funny.
So I guess I'll have to wait for almost a whole year to find out what's going to happen next. I actually read somewhere that M&B are hoping they get asked to do a third season of this. So hopefully that happens.
What are some future storylines and plot themes you guys are hoping for?
I want to see more Bumi, and maybe see Korra actually struggle with something as everything came way to easy for her.