I still think the artwork is among the best, especially, if you put the maid outfit on the mother. The sister's alternative outfit is also quite sexy, though I like the mom more - but that's just me, I guess. I also think the mc doesn't look like a school boy, but rather manly - at least for the protagonist of an M/S games.
As far as the content itself goes, I think the developer will stick to domination instead of romance. I kind of understand your point as far as storytelling and logic goes, though I like the domination content. Considering the setting, the protagonist could also act as a noble protector for the women around him, much like a classic fantasy hero, with the one exception that classic fantasy heroes usually don't fuck their mothers and sisters. They also could start relationships with him out of genuine gratitude rather than coercion - after all, being a ladies' man is much easier, if your are the only man on the planet who was not transformed into a raping demon. As a potential twist the developer could even bring jealousy among the women into play: E.g. the mom and sister fear losing their protector to one of the other girls. As consequence, the use seduction to keep his favor.
I guess, the story would have left room for both routes and variing player descions, wether to be the knight in shining armor or the evil overlord. Maybe the developer offers another approach in one of the next version.