Just finished the series completely a little while ago, after going through all the episodes the last 5 days. I need a lot longer to be able to give a fleshed out explanation of my feeling, but I will give a pros and cons. I gave it a great rating, though by that I mean more "A series with numerous great things, but flaws make is hard to like a lot compared to some people".
Pros:
- The cast. I know people didn't like Mako much, but I even liked him. Each of them got their own backstories and we got to know them more overtime. I loved season 3 when Mako and Bolin met the rest of their family, and everything with Asami was great. Korra, while there were some aspects that were annoying, was a good lead overall. A lot of the side characters got their chance to shine as well.
- Good female characters. The females were the stars for the most part (though Verik was the best of all of them). They did a lot of the fighting, and were quite well developed as characters.
- The setting. Having the technology and just overall developed world was a really cool set piece. Season 1 really shone in this aspect with the team doing car chases with their bending. Some of the later stuff, while cool, was a bit too over the top.
- Interesting plot elements. I know season one wasn't received well, but I loved it. In the con section I'll explain why this and the other seasons failed to be amazing, but the oppression idea of nonbenders was a great idea. Some of the ideas of season 3 were interesting as well.
- Return of Toph. Loved seeing her old yet being the person I liked.
Cons
- Pacing. All of the seasons failed because of this. The first season did well in certain aspects, but the oppressing part failed to a degree, as we didn't see that much of benders oppressing nonbenders. Also the final part was rushed, and while I didn't mind how Amon was defeated, it was not as good as it could've been. Season 2 had more problems of the villain being uninteresting, and while Verik stuff was great, along with just the Mover stuff in general, there was too much going on that it created a season that had some interesting stuff, but was overall okay. Season three had half of it devoted to other things, that the villains were neglected. They were shown to be very powerful, but then they get taken out like chumps. The whole revolution stuff was just swept under the rug. Season 4 suffered near the end, but even at the beginning neglected to really build up the villain. She was just a ruthless tyrant, and I have a hard time believing that she was capable of building up the nation again.
- Too much forced humor. There were many jokes that were cringe worthy. Milo had some moments I liked, but was too much a lot of the times. Bolin, while one of my favorites, was quite guilty of this. I laughed a lot, but I feel that many of them were more out of how stupid they were.
- Some characterization. While the characters were overall good, there are moments that were just bad. I wanted to like Tenzen, but he seemed to make one step forward, two steps back all the time. Worse was Lyn, who was still one of my favorites. She seemed to become friends with Korra, then next season is back to being cold to her. The fact she didn't listen to Mako in Season 2, despite some of his accomplishments, was weird. I don't want to go into details for all characters, but the only one I actually had no problems with was Asami.
- Character skills. Season three was really guilty of this. Characters have really strong abilities, but then somehow get taken out easily. The eye girl is understandable, but when the other two get taken out so easily, it is really annoying.
- Way to advanced technology. The last season lost me near the end. Giant Robot with death cannon, mechs in general, all within three years. I know there were some bulkier ones, but to make sleeker ones, as well as one giant one, was too much for me.
- Korrasami. People are probably going to hate on me, but I feel this was something done to generate more positive feelings than what it should deserve. I liked the series overall, but there were way to many flaws, and when I get spoiled about it from reactions, It seems like an easy way to generate fanfare. Also just seemed like a way to please the shippers. There wasn't enough time to properly build up a believable relationship. I will give it credit though, more believable then the Mako stuff at least. Then again, I found both of them attractive, and I have a thing for girl on girl action, so I guess in the end, I'll give it a pass, with flaws in the building of the relationship.