STORY
I actually loved the story of Kill la Kill because I felt it was the best part of its 'parody' plan. Kill la Kill is a parody of modern anime, with all of its fanservice, skill names being read out in a fight, numbered group of villains, school life, transformation sequences, a huge plot that often has the fate of the world depending on a group of teenagers... Kill la Kill's storyline is a great attempt to be the embodiment of all these elements and cliches, while being creative in its own way.
Why do so many people say that Kill la Kill was overrated? Some of it has to do with how Kill la Kill failed to be a parody halfway and just became that very anime that it was trying to make jokes of. This doesn't stop the great storytelling accompanied with a great soundtrack from keeping you hooked to the show. Besides, while people often criticise the middle portion of the show for not being very valuable to the overall plot, the conclusion to the story is an epic one that you can look forward to. (And I still liked the middle portion, just because it was fun to watch.)
ART
Kill la Kill's art and animation can be described best as 'inconsistent'. Like any other show with a badly managed budget, the first few episodes of Kill la Kill contain some impressive animation, fight scenes, background art and character art, but as the show goes on, the episodes are increasingly littered with amateurish animation and other lazy stuff. Fortunately for Kill la Kill the occassional bad animation and fights that end straight up in a still frame still somewhat contribute to the overall goofy easygoing atmosphere of the show.
SOUND
The soundtrack is amazing. It also comes with the infamous "Don't lose your way" song and everyone's favourite "Ping Pong Circulate" track. It is seriously good, though. I struggle to come up with one bad thing to say about the soundtrack, the timings that they are played at during the events of the show, or anything. It accompanies the show's cast and events nearly perfectly. I personally found Satsuki's theme being overplayed just so slightly during the anime but that's alright because it's a fantastic track anyway.
CHARACTER
I think all the other reviews talk plenty about the lackluster explanation for Ryuuko's motivation to avenge his dad, or Ragyou's plan to [spoilers]. These are some noticeable gaps in character development. However each character in the show is undeniably unique and attractive. The Four Devas, Ryuuko and Senketsu, Nudist Beach, the Kiryuuin family, the Mankanshoku family, and the rest of the city and the academy are all each portrayed carefully well, throughout all the episodes consistently. Rather than having arcs of several episodes to develop each character, they are all developed continuously, in small episodes.
One very important character in the show is Mako. She's not just there for the comedic value, but she really is one of the main characters who is weaved into the main plot and also acts as a deus ex machina who can interject in any situation, whether it be a serious neck-and-neck one or a goofy and funny one, and control the atmosphere of the whole scene. I found her character particularly interesting because of this, along with all her funny moments and the ship with Gamagoori.
ENJOYMENT
If you don't have fun while watching Kill la Kill, I would say you need to see a doctor. But that's just my personal opinion. My point is that Kill la Kill is an anime that is seriously trying so hard to be enjoyable it feels like being enjoyable is its only purpose. (And it succeeds!) You don't need to put much thought into it or understand everything. I recommend you don't overthink it while watching Kill la Kill because that removes some fun and instead reveals some critical mistakes in character development that you would rather not see.
Its entertaining nature is the main reason why I cannot give Kill la Kill a lower score despite the mistakes it makes.
