Isolating the episodes really is part of the bigger problem. The fact that he introduced working titles/episode titles for the updates kind of tells you where is mindset is. He is writing chapters for a book, not scenes for a game that is supposed to be multiple choice, choice based or whatever you want to call it.
As far as the variables go, I don't think he needs to introduce anything at this point. There are plenty of stats and skills in the game. He never uses them. That is the issue. There is one mechanic, apart from the kinks, that has been there from the beginning and that is the "XYZ liked/disliked your answer" thing. Except it never does anything. Never did and with how linear the story is, I can't see it ever having an impact, because what would it change? Would it lock you out of content? Shitstorm incoming. Everything else has been introduced, because he liked the idea, but never did anything with outside the introduction of said mechanic.
Would it make sense to introduce variables like sluttiness, corruption, etc? Yes. Much more than having skills like motorbike experience, or piano lessons. But that would require him to write different scenes multiple times, because the outcome should be different based on certain combinations. Can you imagine how long it would take him? Also it would require planning ahead. Need I say more?