I just don't see this story taking a "MC develops PTSD over what he did to Ryker" turn. I don't see MC shaving his head, taking a vow of chastity and joining a monestary to atone for his sins either. I simply don't think BD is willing to take that much of a turn to the dark side as he has previously and repeatedly stated he just wants to write a happy experience.
Now granted, he's had a complete monster of a year and that might have subconciously influenced his writing a bit, hence the rather shocking mood swerve that concluded Day 7. If I were BD I'd want to beat up 2020 as badly as, or worse than MC beat up Ryker, could be a metaphor, or a catharsis, or whatever you call it. I'm not a therapist.
I think with Day 8 we're seeing BD slowly getting back to that happy experience, so whatever damage was done to Ryker, I'm sure it won't have a lasting negative influence on MC's psyche.