Love the game!
I know you're getting a lot of suggestions thrown at you already, but I got a half suggestion half question to throw on, too: Since a lot of succubus magic is already in play, are you planning on making the hypno/mind control ability they have learnable in future? I'm thinking of winning scenes that could include humiliating the opponent (making them do something embarrassing, could also be comedic at times, I'm sure, like making a usually domineering character apologise for fighting you or something :D) or some orgasm denial content (using the ability like the teacher when you "help" with a lesson to block an opponents orgasm while playing with them).
In battle it could do Ero damage and lower enemy attack slightly; there's other stuff that could also work but I'm not familiar with the software and so I don't know if new battle effects might be more effort than it's worth (like having an added chance to make them fail their attack in the turn you used it because they are trying to avoid looking into your eyes?).
Ways to obtain would likely include Rinny teaching it to you, maybe after you were on the receiving end of the mind control effects of the Succubi/Incubi enemies in Transylvania.
Just something I think could be quite fun, even if I personally prefer to be the victim tbh. :P
Either way I'm looking forward to trying the new new release, this is genuinely a fun game beyond just having good erotic content and I'm curious where it'll go!