The thing is, when you look at the sex, the "craziest" thing happening so far (after years of development and 3 full chapters) is public sex and anal. Both which are not really special IMO.
If you are on the D-Only path, this is what you get. The only thing I get what I did not experience myself is Incest, and this is more than fine by me that it only happens in a game.
Sure, there is sharing, but for me, most models are not attractive. I can get why people like Elena (for example), but she is not for me.
I also dont really have a problem with sharing or prostitution, as long as I (or the MC, to be more precise) are the part who gets to decide. I dislike being cucked like the next person, but having my will why she gets banged by another dude or woman is something I like.
Basically, for me it is the combination of the very vanilla-part of the daughter-path and the lack of attractiveness on other paths. There are something I wish, even tho I know they would never happen (e.g. I would be happy if Dee gets implants. Because she starts to like her big boobs and want to go even bigger. This will never happen, but I know that this is nothing which many people want, so I dont really complain about the lack of Body Modification). Or in general, more depravity.
In the end, taste differs. But I am at the point where I just want to see the ending of the game, the feeling of "OMG this is the best game ever!!!11" which I had when I first played it is long gone.
(But then, I dont pay to play the game, so I have 0 right to decide or complain... And I think in the end, there will be more happy players than unhappy players)