I dunno about being a bad writer, he has certainly not a professional writer background, but it beats 90% of the writing out there in any other games, including Bioware. Writing is not a science, I don't care about technicalities as I don't pay attention to these little things (I'm not German okay?), as long as it gives me the illusion to keep me motivated till the end, I'm satisfied. And yes, I truly didn't figure out that he was the Origami Killer. That's not bad. Couldn't say the same about Bioware games where you already know everything about the antagonist before he/she even opens the mouth.
Not sure what you mean with teenager mind.
......
No, not worth it.