it is a great game, and very much reminds me of HHS+ (Hentai High School +, an amazing game, and sounds like just what you wanted) and would not be surprised if it was heavily inspired from it.
an open world, randomly generated characters, and a main thing to manage (being the head master in that case) that helps you do many other stuff, each character being a romance option, story lines attached to specific characters.
and I'm not sure if this game has it, since i haven't reached far into the game, but the ability to make the school and the world much more sexually open.
but i will give it to this game, the graphics are better, and i think it has better promise, at least if it also grows to have mod support.