OMG, I think you are right on the money with this. I definitely think adding those customization options would make great challenge runs, though I would as a player personally go more for a standard "whatever the RNG gives me" approach to this game. Sorry for the elaborate ideas-guying that follows, I hope my enthusiasm doesn't come off as obnoxious:
What you say about "hard mode" did make me think that player WG does make a good implicit difficulty feature. The game as it stands kind of has a snowball pattern, almost like a 4X strategy game, and I think that could be mitigated if the PC ambiently/unintentionally gains weights from all the different feedist dates they are going on.
This can at least help counter or make it so the late game stuff requires more thought, since the player who just wants to fatten all the girls up to enormous-sized can't just go on dates every day and only visit the gym or jog in the park for the new content when a new weight-stage comes around. Assuming that the player sizes would follow the same arc as the girls' sizes there'd be challenges from:
- Interest of the girls. Both in terms of their commentary, whether they'd give the PC time of the day, break-up, or even the mechanics of the sex scenes. One thing that might make it less punishing is if weight/size just impacts the rate at which affection is gained.
- Employment/Income - Again, the player may well just follow the same arc as that of the girls, and so they might lose progress on their income and eventually be set to a fixed income.
- Mobility/Independence - What if at a certain size the player may not have the energy to go out during the day? It might mean some repeat dates at their place, which has an impact on affection. If the player grows to enormous size, what if the only girls that visit them are the caregivers or (for example) the random apple-shaped beanpole they met and never interacted with since seeking to reconnect?
I just want to thank you again for your work on this game! It's been a real treat to play and the new update has been absolutely awesome!