Fonderu
there are only so many ways to tell the "I'm going to bang my not-family!" story
That's not true.
There are at least as many ways to write an incest story as there are ways to write a vanilla boy-girl romance.
Considering that there are libraries of books written about the latter (and people seem to read them as well) there is plenty of room for good incest stories.
There are already some story drivers in place, such as poverty and the older roommate's desire to move out.
If the dev can make the characters more interesting and increase their character depth, I don't see why it could be a good story.