Well that was a pretty fucking fantastic season of television. I binged most of the show for the first time in advance of the final season, and I caught up right on time. I was quite impressed - I liked the show a lot more than Voltron. Its interesting that this show did better in 13 episodes what Voltron dragged out into several seasons. I think the ending was a bit anti-climactic due to the lack of a big fight, but it was decent enough.
Overall:
+Catra was really well done, and is basically the highlight of the show. S4 Catra was basically S3 Azula from TLA but honestly her entire arc was portrayed really well.
+Surprisingly deep lore
+Fun cast of characters
+Great animation
+Horde Prime made for a great villain. Really, really liked him.
Small issues I had with the show:
-Large cast of characters means not all of them were well developed
-Ice girl's personality changed between S1 and S2
-Earlier seasons were occasionally repetitive
-Bringing back Glimmers dad was stupid
-The show plays fast and loose with distance - the princesses kingdoms are far from eachother, spanning the entire planet yet they can seemingly get to brightmoon on short notice.
-The world building isn't great. Unlike in a show like ALTA, we don't really get a sense for the various cultures that exist
The major issue I had with the show is about redemption. A lot of characters get redeemed, but... do they deserve it? Pretty much all of the characters that get redeemed change their side because they were being treated badly, not because they realized that committing war crimes is pretty fucking terrible. Its hard to root for these characters when they didn't reckon with the fact that they're bad people who have made horrific mistakes that hurt innocent people. The show paints the picture that people can be redeemed, but I don't think it earns those redemptions, at least not fully.