I've come to realize that people who watched the anime series will have an hard time to grasp what the series is trying to accomplish, as it only shows it's true colors by the third arc (I'm counting Uzen has first arc, since everything before it was just establishing characters).
It goes something like this:
Pre-First arc: Mneh.
First Arc: Okay, things are picking up, this may become interesting.
Second Arc: Generic yeah, but it's fun (This is where the anime ends, as far as I was told, btw)
Third Arc: The author comes at this point and laughs at you for having liked the first two arcs.
Medaka Box is simply a satire of shonen mangas tropes. It basically grabs Goku, Naruto, Ichigo, Luffy, Jesus Christ and boobs and mix them together in the most overpowered, ridiculous, bland character of all time. Why is Medaka so strong? Well, the explanation is "Because she is the main character", you can't argue with that.
But I'd say that the strong point is, rather than the main character, everyone else. From Kumagawa, the boy who always loses, Zenkichi, the true main character, or even a villain that, even though she's the most OP thing in the story of OP things, simply refuses to fight Medaka because "Main characters always win against last bosses."
The third and fourth arc are what make Medaka Box what it is, because it's the one that really explores the ridiculousness of battle mangas, but not in a bad way. It's never "Shonen mangas are so stupid and ridiculous, you should be reading actual good things." it's more like: "Shonen mangas are so ridiculously stupid, but so what? They are supposed to be, it's what makes them fun, and that's why you should read them." And that's true, no matter how many complex and serious stories are there, there will always be space for simple fun stories too, and we should enjoy both.
So that's why Medaka Box exists, and you'll either love it or be pissed off by it.
Minha nota: 9/10