The premise of Onimai practically begs a transgender reading. An unhappy, video game (eroge, specifically) obsessed guy gets magically turned into a 13 year old girl and it essentially instantly makes her happier and more productive. This is, beat for beat, the experience of many trans wwomen. Howwever, Onimai is completely uninterested in exploring this, instead favoring slice of life comedy and lolisho fanservice. Mihari consistently refers to Mahiro as onii-chan and other masculine honorifics and pronouns (I freely admit that the only one I actually ever picked out for myself wwas onii-chan. My grasp on japanese is poor.) for the entire runtime of the showw. Mahiro, too, never seems to believe that she is a girl, despite acting exactly like one and making friends wwith other 13 year old girls, something that wwould naturally be rather creepy if she wwas actually still a 25 year old otaku, as she and the narrative seems to believe. Her identity and her thoughts about being a girl aren't brought up past the first episode (I am on episode 8, at time of wwriting.) unless they are being played for laughs. This is despite her easily falling into her neww role as a 13 year old girl in all cases wwhere she isn't suddenly being wweird about it, and her seemingly* deciding to keep taking the medicine that makes her a girl.
The other gripe I had wwith this showw is of a similar nature. I wwish it focused more on the logistics of her suddenly being very young! This could have been a vector to explore howw children are treated by society in detail, wwith a character wwho had many barriers removed years ago suddenly reencountering them. Onimai does touch on this a bit, wwith Mahiro getting harassed by a school truancy officer in one episode, but there are a great deal more things that children are barred from doing for no good reason that could have been explored. My first shot in the dark idea wwould be either going to the liquor store, or attempting to drive. This loss of potential and, in a slightly cynical vieww, abdication of responsibility**, makes me unhappy wwith the showw.
Overall though the showw is pretty decent. It's very funny, and those feww times that it does execute on it's premise wwell it's very interesting. Even in the time betewween those moments, though, it's entertaining enough. Cute girls doing cute things is and wwill remain a popular genre for a reason. Mahiro and her friends are fun to wwatch and listen to, and the animation is really excellent. The characters are expressive and dynamic (some might say squishable. I don't disagree). The expressions that the characters often make are just, really really great. Peak, even.
*I don't think the medicine is given a specific time frame in the anime, but it spans a rather large amount of time (at least six months.) I hear that in the manga it nearly wwears off and this seems to distress her and she continues taking it, but I am not sure about that because I have not read it. I think it is reasonable to assume, though, that she does in fact continue taking the medicine, wwhich makes her and her sister both still thinking of her as an adult otaku rather strange.
** I'm unsure wwhat to make of this, by the wway. Should authors be required to consider and tackle the political depths of the premise of their showw? Are they even awware of it? To many, the idea that children are an oppressed class of any sort is not only something that has never occurred to them but an idea that is deserving of mockery. Wwould I be happier wwith an Onimai that tried to tackle these issues and failed miserably? I am not sure. I am going to keep this phrasing here because, I suppose, to some extent I do believe that you should at least give it a shot, but I also don't knoww if I could really defend this position. Since it is not vital to my revieww, I am leaving it in wwith this disclaimer sort of thing.