Stacy for me. Her (pretend) bored uninterest coupled with all of her cosplay etc. seems fun. Although I wouldn't mind Draga. What I would like more than anything is more connection between the paths - like why would Mallory rape you at the school if you're in a path with her, and also act like she doesn't know you? These are little details and hard to clean up but the game could make more sense if they were. Same thing with Claudia coming by to get the tax when you are on a path with her.
I say they are hard to clear up and maybe code-wise they are, but writing-wise I think it should be easy to take care of
A good Draga route would be helping her train to become an Olympic-level fuck machine. Its not really about love, but about becoming teammates and working together. It would be about getting the gold in their respective roles. Draga becomes a medaled Fuck Machine and the MC becomes a medaled Fuckboi.
Stats can help track the duo's progress. Special "workouts" can help Draga get her dick/cum/domination levels to 1000+ and you can also train MC's oral/anal/submission skills to 1000+ too. Tracking your health and insuring the MC doesn't die from all of the fucking could be another element. And pushing your intelligence into the negatives somehow would be an interesting idea too.
Once her route is finished your skills will start decaying back to 100 since you can't train like that anymore.
Also Draga needs to be redrawn a bit. Her anatomy isn't exactly right in the talking scenes.
I made a quick sketch of a good Draga outfit just because I can I guess.