the good/bad thing about the seer is it's a pretty easy role to play. And it can still reward incompetence. If you are a n00b seer and you peek someone, it doesn't matter who you pick, you are still going to have a net gain. You are getting closer to solving the puzzle each night.
A vigilante on the other hand, can be just as powerful as the seer, if timed right. However, if you fuck up, and choose the wrong target, you seriously can fuck over your team. Playing the vigilante is much more skill based.
Same thing with watchers. If you are a good player, you can gain just as much, if not more information by correctly targeting the right people to watch at night. But if you choose the wrong person, you'll come away with nothing.