Is it the kinks you can get up to?
The situations you find yourself in?
In your humble opinion, what is the appeal?
I don't really care for games where you're in complete control, the results are too often one-dimensional. The appeal to me is purely physical and altering the integrity of a character's mind renders everything they do or say invaluable to me. However, given the way you approached the topic, I decided to think it over and write what this game would have to offer for me to play it regardless.
Assuming the game's main focus is on heterosexual content with a male protagonist:
First and foremost, there would have to be consequences. While the story is building, the MC would have to be put in circumstances where he would use his powers to accomplish things that don't necessarily benefit himself. There has to be a dynamic where the MC isn't just trolling the yard and making people suck his dick. The story would have to be able to stand on it's own rather than relying on kinks as a crutch (like 90% of games with landlord content), in other words, because you're corrupting your sister doesn't mean it's ok for the story to have no substance. If the story has choices, there would be no "right" choices, those aren't choices at all and I wouldn't download the game if it required a walkthrough.
Story aside, the sexual content would have to adapt to my tastes. I support all kinks with the exception of raping women in their sleep (if she's awake then rape away), but if I happily and greedily shove a foot in my mouth and lick between the toes it's an insta-delete. A good game can go from start to finish with no sexual content (Yup, I said that).
Overall, emotional intelligence... and a meaningful story with meaningful choices.
Good luck with your game, friend. Gathering information from players puts you in the upper-half even before considering the quality of your work.