I think it had severe pacing issues. I like the fast-paced-ness that was legend of korra, but when that comes at the expense at learning your characters, I just don't care as much. I think if each episode had been an hour long or if it had been a full-fledged season, the creators could have done this better. But they were trying to cram way too much into a mini-season. They should have known better. It would have made the show tons better.
I don't understand why the creators had romance in this season at all. You didn't know the characters yet, and they threw them into a messy relationship woes. So all we know of these characters were how they were in a relationship. You know what's also sad, Mako and Bolin were pretty useless to the story after the Pro-Bending Tournament. Especially Bolin. Mako only had Asami and Korra to be connected to romantically, so if you take that out, he seems to be an after thought. You didn't get a sense of friendship between Korra and her avatar team that Aang had with his (yeah, his team had 3 seasons, but there's no reason Korra's team shouldn't have been more developed). I think that is because of the pacing issues and the fact they shoved the romance in there so soon that anything that was not connected to it, didn't matter.
I mean, it's nice for once the guys in a relationship thing are flat (you know how many kid shows have it the guys are fleshed out but their lady romantic counterparts aren't?). At least Korra and Asami had plotlines. But Mako and Bolin did not. Their plotlines revolved around Korra or Asami (or even as in the case of Bolin, not at all) which is terrible writing.
Also, wtf, dues-ex-avatar at the ending. It was way too neatly wrapped up with Korra getting her bending back. However, given that the creators only had one season to work with and didn't know they would get a second one until after all this had been made, I'll let that slide. Gotta let the kiddies have an uplifting ending after having a suicide on a kid's show. YEP.
(Though honestly, I would have loved a mini-arc where Korra had to get her bending back the hard way (I mean really, that could have had lovely character development) and not Aang coming and going "here ya go!").