Fantastic GDC talk, been a favorite of mine for years.
The only slight disappointment about it is that he doesn't really go into the more elaborated applications of the Backwards-Scriptwriting technique that were proven to be so insanely effective in Nier.
He kind of touches on it in the example he gives about having a strict friend, where having a backstory that makes this superficially unappealing personality trait, understandable and endearing once revealed. I guess its hard to clearly articulate as it deviates from the strict linear narrative model he uses in the slides, although its just in essence two "emotional peak" character arcs where the latter one alters our understanding of the previous.
That being said, what should be a truly fundamental understanding that the writer needs his characters to EARN their place in the audiences sympathy seems to be sadly rare in a lot of modern games and movies.
Yoko's a total mensch though. Despite his unassuming, self-deprecating presentation this stuff is straight up brilliant. It cuts through to the heart of what really matters in a way rarely seen.
