Oh writing is very important as well. I shouldn't have excluded that in my initial reply to you...
I just don't care for the drama, corruption, taboo and all that.
I just prefer games where there is a true romantic connection based on love that the MC has with his girls.
And if that's incest too, with M/S, B/S and if you write it in a clever way even F/D with one MC then it's peak.
Unfortunately there are very few games that fulfill that.
But I like a true romantic connection. By corruption I didn't mean making the girls as lifeless dolls to breed, but actually going against the current norms of society and "fighting" for that.
For example, if you ever played Crusader Kings, you can play as a culture that despises incest, be shunned about that, and reform your culture as one that accepts it. You can even make it a virtue on the religion. That's the kind of thing I meant about "corruption", going against the norms of society.
Let's be frank, not everyone likes it, and some characters may do like it, but are afraid to do it, and need "time" for it. Like a son that helps the mother and sister from an abusive father, and so on. Those kind of stories is what I like. But something like "hey bro you're hot, let's fuck" doesn't give substance to the genre.