Hm. I'm not the author of the game, I don't know why you're speaking to me as if I am.
I'm another fan who is merely offering his perspective on things. As far as the unusual approach is concerned, I don't understand how it is unusual when the "Hentaiverse" is loaded, absolutely loaded with works who have their Succubi be sexy, domesticated ladies who deliver amazing sex and merely capture their prey afterwards, if anything, the "I'm going to drain you until I kill you" kind of Succubus is a rare sight to behold. Ratio favours the first type, at least in my experience.
Things with monster girls-focused works could be slightly better, but even in those there are ones who keep their victims alive, going as far as turning them into husband/wife/source of nourishment.
Back to Monster Girl Dreams, I understand it sounds like I'm "white knighting", but again, this homepage is stating just what kind of content one could expect to find in MGD, for those who don't bother to read that stuff, the game itself tells the player how things work as he/she is making the first steps. Well, it seems to be fairly easy to mod, so, nothing is theoretically preventing anyone from creating a more dangerous kind of enemy.