I feel like this is an awesome manga concept that took some unique ideas and utterly wasted them. A potentially very emotionally charged premise is tossed aside or even transphobically dismissed by much of the writing. The story barely focuses on any of the gender bent characters and instead on poorly-developed 100% female characters. While it's not a bad thing to have a diverse cast, writing a gender bender manga and focusing almost wholly on the born girls is like going to a Chinese restaurant and only ordering a cheeseburger and fries.
And oh my god, the ending is a disappointment. Not just that it's *bad* but that it too could have had potential. It would have been an interesting twist-ending if a half-volume or more was devoted to it properly becoming an all girl's school and the adjustment of the newcomer. But as xyzzy said, you can practically taste the cancellation.
I would very much like to see a manga with a story like this written someday and for that theoretical manga to make soup from the bones of this one.