It is mainly because of the reasons that Buu pointed out in the previous post. I will quote:
"The first is freedom. I think option one(CoC) limited the mc to follow the dark god and do along with all his plans especially if he gets killed if he doesn't obey. While option 3 (DM) limits him to a dungeon in some small town. Who knows what he will get. Doesn't get to choose his woman, just whatever comes through the door. Also if he gets discovered he can't run. Either plot armor, stay hidden, or have high-leveled people come and destroy the dungeon.
The second reason is moral questioning. The first option he has no choice. He is a follower of an evil god so he can brush it aside. Option 3 he is already down on his luck so why not be bad. However, option 2 has the option of him questioning and fighting himself on choices."
As the first reason points out, in 1(CoC) and 3 (DM), our protagonists will be constrained, having no agency over themselves. In option 2, however, our mc is free to do as he pleases, as long as he satisfies his growing sexual needs, that is.
The second reason is that, as he mentioned, there is no self-struggle on the moral compass. Although there are workarounds, that would be a bit fake.
I will put these two ideas in the drawer for now.
[collapse]
First off remember in the end its your story. Take the polls from people. Get ideas from them that you like. But at the end of the day it is your story. If you let other people control what you do too much you won't enjoy the story.
Personally I picked option 1 because I think it will be easier to do and less plot armor/over powered mc that could happen down the line for the mc. . . Plus it keeps the mc ground. Funny enough when I was reading the description for some reason a s*x vampire came to mind. I guess an incubus and a vampire have a lot of similar qualities.
Question on option 2 are you going for a doppelganger with the transforming stuff? This route does give you the option for different types of plays with goblin, orc, and other monster races. Also might effect his psyche more. A lot of times in fantasy/superhero stories doppelganger go through an identity crisis and forget who they are and even if they were originally male or female.
Heck if the mc is turning into monsters this might be even worse. What am I? Am I a human, goblin, what? On a side note it does open up the options of monster interactions or team ups but I do suggest not forcing him to remain as a monster. Make it so he can go back and forth between human and monster.
On a side note I think the experience gain through sexual actions should be on both characters regardless.
Best of luck