The female player character model could do with an update as well as more granular stages to their gain. It would also be nice to have NPCs react to your size.... Perhaps that is just my feedee brain though!
NPCs do react to your size! When you interact with an NPC for the first time after gaining weight, as long as the NPCs themselves don’t have a new weight stage reveal queued, you get a “reaction” dialogue line. Furthermore, if you’ve gained weight, lines reacting to the player’s gain get added to the dialogue pool with the “talk” button (you can press it multiple times).