Kill la Kill's final episode was frustrating. So frustrating that when I think about it too much it makes me want to cry. I say this not because it was bad: it wasn't bad, it was good, and I had almost nothing but fun watching it (all three times in the last three days). I say this because the series itself was unbelievably good, but I felt like the final episode just didn't quite conclude the themes as well as it could have. I had a feeling this would be the case in the run-up: episodes 20 and 21 drove the emotional stakes to a height that I was convinced would be umatchable in the finale; the show had also been very rough around the edges for much of its run, replete with interesting ideas but having trouble stitching them together into something that felt truly complete. I knew that even if the last episode were a total wash it would still have been a fantastic ride. Even so, I damn well know Kazuki Nakashima can do better than "HUMANS ARE HUMANS! CLOTHING IS CLOTHING!"
However, Gurren Lagann had a thematic completeness that I haven't seen in any other piece of media, full-stop. Taking the ridiculous sounding idea of drills as its basis, every possible avenue for this concept was explored and exploited, from digging and breaking through things to spirals, unending cycles, infinite escalation, DNA, evolution, and progression. These themes were all made use of in the grand finale: the final mecha being the biggest ever seen; the Anti-Spiral being a race that had halted their own evolution to bring an end to the infinite outward progression that they believed would end the universe; Lord Genome's sacrifice, embodying the idea that the previous generation needs to make way for the next; Simon's final speechifying, monologuing on the nature of a drill, turning round and round and making progress with each revolution, tying into the double helical shape of DNA and the growth that represents. What was most important, however, was Simon's actions after Nia's dissolution. Presented with the option to use Spiral Power to revive all those who died in battle, he refuses, mirroring Lord Genome's final words and stating that the dead should remain dead in order to make way for the next generation. In a story whose defining principles have included near blind resolve, hot-bloodedness, and growth, the ending, the ultimate solution to the ultimate problem, is insight, sensitivity, and restraint. This is the reason Kamina had to die, and why Simon had to take the helm. This is the completion of his character arc: he had what it took to drive Spiral Power to its potential and defeat what needed to be defeated, but most importantly he had the wisdom and the calm to see when it was time to stop, to hold back. The bit in the epilogue with the kid trying to drill open a coconut reinforces this. Simon's advice to the child is to drill more gently, and the fruit yields when he does so.
Kill la Kill's ending doesn't really achieve anything on this level. The central theme has been clothing, but it felt like the most important parts of the finale didn't make clever use of it. Ryuko dons the Goku Uniforms of every other character in order to power up for the final battle, which was great, but while Senketsu Kisaragi's design does look awesome it doesn't feel like a true progression, or reflect the fact that it represents the contributions of many different people the way Tengen Toppa Gurren Lagann's does.
Ryuuko finally reconstructing the Rending Scissors was cool, and I'm not actually even mad that they proved useless, but the way she ultimately turned the tide of the battle was by some backhanded "I get stronger when I'm closer to death" asspull and an alien absorption technique rather than anything to do with actually wearing clothes. She and Senketsu speechify heavily on the fact that each of them is neither human nor clothing, while being both human and clothing, but holy shit it doesn't fucking mean anything, and Ragyo lampshading it doesn't excuse how sloppy that writing is. (Also, it seemed so obvious that I just assumed it was the case, and I've seen it stated on wikis, but is it even stated in-universe that Senketsu has any human, specifically Ryuko's, DNA in him?)
There were good aspects to Kill la Kill's ending. Ryuko, rather than simply trying to destroy her mother after unraveling her scheme, offers her the chance to surrender and come home peacefully. This signifies an important concluding step in Ryuko's arc: she has progressed from a juvenile delinquent wracked with self-loathing and bent on revenge to someone willing to forgive a completely unforgivable person. However, this whole concept was given a single line of almost throwaway dialogue, and I think it's more important than that. Senketsu's final speech was actually excellent, and made heartbreakingly poignant use of the clothing theme, but it's not quite enough.
What makes it most frustrating is that I can honestly think of a better way to have done it. We've had the reveal that Ryuko is a Life Fibre/Human hybrid, and plenty was made of it from an emotional standpoint (her terrifying face after learning of her true nature is one of my favourite moments in the whole series), and it heralded a significant boost in power and growth as she came to terms with it, but the obvious implication was never touched upon in a meaningful way. She's both human and clothing, but what is clothing? It's something a human wears. So what if, when she impaled herself on Ragyo's massive spike, instead of just absorbing Shinra Koketsu, she enveloped Ragyo completely, becoming her clothing? That, to me, is an interesting and clever solution, and also would do much better to signify that Ryuko has truly come to terms with herself than did the mindless shouting we got. It would actually have been thematically relevant. And then that can lead into a sequence reminiscent of what happened when Ryuko had Junketsu forced onto her in episode 21, only without the squick, the creepiness, the manipulation or insincerity. We can see Ryuko really, truly trying to reconcile with her mother and even her half-sister, Nui. Both these characters are flawlessly detestable villains and every second they looked unhappy was delicious candy to me, but I would have loved to have seen Ryuko really going to lengths to try to absolve them. Of course, they can reject these advances. Ragyo can struggle out of her clothing, and then the rags of Shinra Koketsu recoalesce into Ryuko and Senketsu's form, and now she's absorbed the Absolute Submission ability so the ending can continue as we have it now.
I know what I just typed is essentially a big load of fanwank. However, I feel I need to state it to get my point across regarding what I think was wrong with the ending and how I feel it could have been done better. I always feel bad saying stuff like this because Hiroyuki Imaishi is a genius and I'm a lazy hack, a mediocre animator, a crappy draftsman, and a terrible storyteller, but I have to get this off my chest.
None of this is to say that I think Kill la Kill as a whole is bad. If it weren't for the problematic aspects I noted above it would be a 9/10 series easily. I'm just frustrated because I think it could so easily have been a 10/10.