Thanks for the ideas, guys.
I'd ask him if there were any key parts in the story that he would have done differently with the benefit of hindsight, apart from the 'lost chapter' of course.
We touched upon this last time by asking him was any part of the story especially difficult (to which he replied no). But your question would somewhat require him to admit mistakes.
In Berserk, you have portrayed disturbing moments by holding back details such as not showing Griffith's exposed after his prolonged torture. You have also portrayed disturbing moments with overwhelming detail, Casca's rape as an example. How do you know when to inundate the audience with detail and when to hold back?
Not a bad idea, but there really aren't
that many examples of what you describe. Really, there's just the one. And I imagine he would reply something akin to: Instinct. It's also getting close to asking a comedian to explain his jokes.
I know it seems like I'm being critical, but I do appreciate the variety of questions. I'm just trying to find questions that will encourage him to reply should we ever write him a second letter. Whenever I formulate a question, I always try to consider his range of replies. Does the question imply criticism of his work? Would the answer require him to give away parts of the story? Or ask him to explain his storytelling method to a degree that would be uncomfortable? On top of that, there's the whole "always be super polite when asking questions of Japanese people" thing to consider.
Here are a few questions of my own, to which I invite the same amount of criticism as I have offered

- How long have you had the idea for the design of Griffith's capital city?
- In the past, you have visited other countries for research. Did you visit anywhere outside Japan during your 1-year break from Berserk in 2013?
- Which minor characters in Berserk do you enjoy the most, and think fans should appreciate more?
- Your artistic style has become increasingly more detailed over the years. It must be quite a burden to keep that quality so consistent. Is there a personal conviction that keeps you from employing a more economical approach to the art?
- What is the meaning of the furigana "ジャンアーニン" in the episode title for Episode 243: Superior Being?