Looks like the comment was removed, but a quick correction: I read "Futanari Joshikou no Onaho" for the first time when I was asked to make an adaptation of it, in that comment that is now deleted.
As for temptation... HELL YES!
Both of your ideas would work as a sequel to Futa School, so I'll definitely keep them in mind!
Sorry for being overly verbose, but the second option sounds more manageable. It's also very easy to segment, and thus control just how much content you want to add without feeling disjointed.
Just have a school with several classes filled with generic, nameless students. Their two values are "academic grade" and "lust." The former grows when you assign a named female teacher to them, the latter grows by itself over time.
The teachers, on the other hand, have three stats - the subject they teach, their willpower, and the hidden fetish each one possesses.
Once a class's lust reaches a certain threshold, they start pestering the teachers for sex, which lowers their willpower. At that point you can have either the principal serve as sexual relief, the teacher to do it instead, or ignore it.
If the principal does it, the lust value is safely reduced. But she can only "service" one class at a time.
If a teacher does it, the lust value is also reset, but their willpower is permanently reduced, thus making it easier for her to be pestered for sex the next time.
If the lust growth is ignored, or if the pestering is successful (the teacher's willpower hits 0), the class period is wasted on the class ravishing the teacher, and their grade is lowered.
Then you add in named students, with each one having a fetish of their own. If placed in a class with a teacher whose fetish is compatible with their own (like a submissive teacher having a class with a sadistic student) the student's fetish value increases, and they begin corrupting the teacher.
If they succeed enough times, the teacher becomes permanently corrupted, and can no longer deny the given student their advances.
Then, if you'll feel extra ambitious, you can introduce a mechanic where, if multiple students corrupt the same teacher (to bring back the example, the submissive student is corrupted both by a sadistic one as well as one into bondage) they turn her classroom into their playroom.
That way, you can infuse as much or as little content you want over time by adding additional teachers, named students, and subjects.
