I wasn't so much upset at the fact that it only lasted 12 episodes as I was that it ended on a completely unresolved note.. Like, they didn't settle anything at all. Barely explained anything about the "fairy war" and the "F" group. MC didn't choose a girl. It went nowhere. Nothing was resolved. Felt like a really shit way to end the show.
Based on a light novel. When any anime's based off a light novel, or even a manga that's still running, I don't expect the anime to really settle. Some people were saying that Kawai-sou ended without hardly any progression, but then I heard the anime more or less caught up to the manga, so well... there's no helpin' that. Sometimes 12 episodes just ain't enough... or rather, it's never enough but it's usually all the author gets.
For what it's worth, I did enjoy the series. I was a little sad they didn't use their superpowers more often (if even for mundane things) - the premise is that they have them and things are still normal, but instead we see them being normal and are occasionally reminded, "Oh yeah, they have superpowers. Meh, moving on." The characterization was all there though, and better done than in most series, and just for that I still rate it highly. It's just... it carries some baggage, which everyone's mentioned before.
Moving on to other things in my long queue though. Durarara is first up. Maybe I should finish some of these shorts while I'm at it.