If you add another Investigator (let's just call it the Inspector) with half-different results, you could have a new mechanism where TIs compare results to narrow down someone suspicious' true role. Instead of Inv giving 3 possible roles, give 4, and do the same for the Inspector. Ensure that the roles overlap twice, so if the Inspector and Investigator compare results, they've narrowed someone's role down to two possibilities (one Townie and one Evil/Maf).
Example: Pretend that there are 8 potential roles in this game: T1, T2, T3, T4, M1, M2, M3, M4.
An Invest result for a T2 would look like this: "Your target is a T1, T2, M1, or M2!"
The Inspector result for that same T2 would look like this: "Your target is a T2, T3, M2, or M3!"
By comparing results, Town knows that this player is now either T2 or M2.
with real roles, it could look like this
Investigator results: "Your target is a Vigilante, Doctor, Mafioso, or Forger!"
Inspector results: "Your target is a Doctor, Spy, Forger, or Godfather!"
By comparing results, Town knows that this player is now either Doctor or Forger.
Investigatives now have the incentive to work closer together, and if they do it successfully, they've really trapped evils into a small claimspace. Maf now has more claimspace at the beginning of the game (now they usually they have 1 Town role within their inv result), and can claim TI to throw TIs off their trail.
I think this change would make for a more collaborative game for the Town, which would add another layer of trust and deception to a game all about trust and deception.
Thank you for looking at my suggestion!
edit log: took out my anti-sheriff angle which is separate from this rework/addition suggestion (as much as I still agree with it)
