To be fair to the game, I don't think that this is that. While all four main girls may be options they will not remain so if you don't make them a priority. Like this update you were finally able to consummate MCs relationship with Lucy, but only if you put her first. I imagine that the other paths will unfold in a similar fashion. You aren't going to end up in a harem with two pairs of sisters. The world as it has been built doesn't support that outcome. I think that if you try to balance points between all four you will lose all of them. I would love to be able to play through to that outcome, actually.