Overall the finale was quite decent, with a lot of good fights and bending action going on. As far as the writing goes, though, it still wasn't without problems, such as Asami׳s dad being thrown in only so he could die and provide a tragic moment, only that it wasn't effective, because I sure as hell didn't care about him. It felt contrived and unnecessary. Plus, the conclusion didn't feel too satisfying. Felt like just another end to another chapter rather than an end to a story. Korra's and Tenzin's conversation at the end was a nice touch, though, because of their past student-mentor relationship, so it was fitting.
As far as the rest of the season went... meh. They couldn't manage to raise the stakes high enough for it to feel like the "final chapter". Going for the end of the world and fighting the ultimate evil back at season 2 was a dumb move because they could never top that. Kuvira never felt threatening enough on her own, and she only managed to be an obstacle because Korra was going through her not-so-impressive character arc. The season had some potential at the start, but didn't manage to be good.
Speaking of which, Korra seemed really "not there" as far as the center conflict was concerned. I get it was somewhat the point because she had that character arc going on, but only in the last 2-3 episodes did her presence actually felt meaningful. More on characters: as the seasons went on, Bolin became more and more annoying, unfunny and stupid. Mako barely had any character development outside of his failed relationships, and in this season he was probably one of the least important characters. Prince Wu was abysmal and a really annoying character.
The main difference between this series and the Airbender series is that while the latter was a one big story, this show had four individual stories that weren't really connected (besides the mild connection between the third-fourth). This isn't a sin because in theory it could've worked, the problem was that none of the individual stories was written well enough, and there doesn't seem to be an overarching theme going on in the grand scheme of things. This series is about Korra dealing with different avatar related issues and threats while growing as a person - it isn't a bad premise, but the writers badly tackled character writing and stakes, and forced us way too many times into badly written romances, repeated character beats and deus ex machinas.
So at the end of the day, even though there obviously was an entertainment element going on in this series and some things were done right, I don't think this show managed to be good.
I'm using an iPad now because my computer is still being repaired, so it's a bit uncomfortable to write. There are a few minor things I'd like to voice my opinion on, so I'll do it when I get my computer back.