I had been thinking of giving the Seer more specific results, like 'Human, Cultist, Vampire, Demon, etc'. Might be interesting to have different 'levels' of Seer, though, that get more accurate results the more powerful they are. Kind of like the Paranormal Bodyguard system.
I also figured out an easy way to handle the Priest situation. Make normal Priests and Tainted Priests. Tainted Priests always raise the person as a Demon instead of whatever they were before. The priest's type would NOT role-flip on death, so there would be no way for the town to know if the raised person was in fact a townie.
New role idea: Sexton (graveyard keeper)
The Sexton is in charge of the graveyard. He is notified if anyone does something to a body in the graveyard during the night. So he'd get messages like 'The body of so-and-so was disturbed during the night. It is missing the next morning'. He wouldn't know exactly what happened, but he'd be able to alert the town if that sort of thing happened and the body didn't show back up.
Oh, and another interesting role: Ghoul SK
Can choose to EAT a dead body during the night or perform a Night-Kill. If he eats a dead body, his next Night Kill is unstoppable.
I kind of like the idea of Supernatural being a game where there could be many, many dangers that could come at the town. Which ones would change from game to game, and the interactions between them could be very interesting.
Another possible role: Sage, or maybe Astrologer
The Sage studies the signs surrounding the coming catastrophe, and can warn the town of the dangers that they will face. So, a power role that's really only useful day 1 but would be able to tell the town that they had to deal with, say, Vampires and a Ghoul or Werewolves and a Necromancer.