I think it'd over complicate the game. I like how simple it is where it is. A detective idea sounds nice like in Mafia, but the Imposters are already at a disadvantage (compared to number of crewmates). Adding a detective would just make the odds worse. Maybe in a 3 imposter game-mode, potentially. A detective may have some sort of ability to know who the imposter is (like subtle hints) so they could convince the crewmates to vote off the imposters. I think it'll add an extra layer of sophistication and strategy to the game!