Hmm, perhaps keeping in theme with Sleeping Sister somewhat, perhaps a daily life type of game like My Oblivious Milf, where you do perverted things to your family, like groping your mother whilst she's cooking breakfast, cumming in your sister's morning coffee, using your aunt's panties as jerk material, peeping on your cousin showering, etc.
this way you can have more variety, rather than just sleeping situations, heck, you can possibly even incorporate Sleeping Sister as part of the game, using the sleep mechanic. Perhaps a day cycle mechanic, maybe not as varied as MOM, perhaps Morning, Noon, Evening and Night will be just fine.
I linked this post on reddit's r/lewdgames and r/NSFWgaming as well, hopefully you get more responses and players,
I quite liked Sleeping Sister.
comment from u/nudes_welcomed
Sleeping sister was really good, great mechanics and progression.
Not sure what else I'd like them to make, but while I enjoy some text based games my favourites usually have images. Even just some form of stock images would help. May not be possible with the developers situation but if they could find a way that would be great.
Maybe the next game could include moving around the house and having other interactions and dialogue, more characters to interact with. Combine that with the a similar sex mechanic.