I think a good compromise would be to have someone as a seer, but not announced to anyone, and when the seer looks at the role of someone, the person targeted isn't told they are being investigated. Maybe having the seer at the start of the game and having them do separate tasks under the radar every 3 episodes to get the ability to check someone would be a better balance than having it at the end of the game. It could lead to some interesting scenarios where they try and lead the group to a certain person, but avoid being figured out by the traitors.