To be precise I prefer to have sex only with the girl I love, and prefer to avoid having sex with the others. And I'm not against harem games if the game lets me choose which girls I take into my harem. I only dislike enforced, unavoidable harem games, where the protagonist unavoidably gets into relationship with everyone regardless of user choice.
Story mode sounds good for me, the story is the soul of every game. You made a good into story, because you actually care about making a good game.
Thanks for letting me know about the plans with the sandbox part.
:)