Hello Andu,
Sorry for the late reply.
You have actually a very good point, but also take in mind in the game you're taking action from a guy who is already in a certain way, so what your decisions in the game are more like driving a car, if the car is not able to do certain thing, it will have problems.
For example in the game, the player can't drink alcohol without coughing, or control the erection of his dick... so you can take decisions but you can't actually control the body of the chacarter (or force him todo certain things without having certain points, like receving anal sex, for example).
I understand your point of view, like more options could bring a more extensive experience and be able to perform oneself as in the character, but in this game this is a bit limited, at least for his physical body experience.
Thanks for your comment and I hope you can still enjoy the game. ^^