I would to suggest a potential mod for NPC's that only becomes active during dialogue mode.
It's purpose it to provide a little more realism to the chat window by making the person you are chatting to seem more alive by adding small but gentle movement elements. It also allows itself for a new customized NPC system that extends the potential of illustrated NPC's.
The faces of the NPC's are now based on the "2d vtuber" model system.
It would be considerably more simplified but allows for a mix and match of backdrop, clothes, neck, face shape, eyes, hair, skin tone and provide gentle movement.
It's just an idea but I don't know if anyone has ever tried to add even slight movement to the portraits. Even just gentle eye and hair movement in an 'animated gif' style would increase immersion.
Hoping to inspire others.