I visited a screening of Denpa Onna at our local fabulous anime convention, which ran for 2 episodes. Such expeditions are often useful; that is how I came to know Nodame and Mahoraba, for example. This discovery wasn't as profitable, but at least I watched it now and I'm free to bad-mouth it.
Over the years I gradually became disillusioned in SHAFT and Shinbo. I think the last his work that was watcheable was ef. Denpa Onna came very close to staging a comeback for them, in a way that Somethingmonogatari could not. Animation is still SHAFTist, but quality is unusually high. No photos for backgrounds, here. There was one instance where a stationary fabric pattern was used, on a blanket into which the human burrito was wrapped. The 3D was kept in check. The comedy is Arakawa Under Bridge redux, but again, smarter than back then. So, what's wrong?
To begin with, the "everyone is broken" setup is not particularly attractive as a base. Upon that, the construct of "cute crazy (girl)" is mounted, and it's not actually as cute as it was in Mahoraba. We have a chuuninbyou so advanced that the patient has dropped out of school purely because she was too disfunctional. A Sword of Damocles is hanging upon all this, where the dude ultimately does nothing to cure her, because SHAFT hoped for more seasons. Really didn't want to stick around to find out.