Well, the child doesn't have to be actively shown on-screen to be a part of the story told; she needs to the object of conflict.
- Does Julia stay classy and not succumb to the pressure in order to be a better mother to her daughter?
- Does she reject temptation this time around precisely because Penelope was born from her previous affairs?
- Does Julia indulge herself because she doesn't regret anything from PE1?
- Does Peter really have a handle on playing daddy to a daughter he is clearly not the father of?
Start answering these questions, and you got yourself some good drama to go with your ero-scenes. AVNs should be about exploring taboo topics more in-depth, not just superficial scratches on the door of drama.
It really makes no sense to give the players a chance to see the consequences of their actions in PE1, only to write them off & ignore them in the 11th dialogue line. Even dumber to use existing characters, to tell an already-existing story, that players can play whenever they want.
Nothing about PE2 says "evolution", just a replay of events we've already seen. And it is that missed potential that hurts the most.