Oooh! Exciting!
I've technically played in one Duelling Wizards game, but I died very early. Still, here are some suggestions/comments:
1. I agree the Seer is redundant.
2. Not sure about the Visitor. I like the idea of keeping some uncertainty about the role's alignment, i.e. a possible wolf- and yes, in that case there should be two. Even so, it sounds like the sort of role that can skew a game rather easily, so needs careful implementation.
3. What, to you, is the "usual Hunter role"? Logical or non-logical? Similarly, what are the rules for Ranger protections?
4. Are roles normally revealed on death? Or is this like other games with a Dead Thread in that respect?