Definitely agree, but balancing will be hard, since the new neutral classes will be competing for player slots with BD and the other neutrals. Also, the new neutrals would need to be, uh, neutral enough so that they aren’t effectively just extra BD members. It’s important that they CAN be beneficial to BD without being forced to, because if they’re reliably in favor of one faction, that means that games that roll certain classes will be imbalanced.
Right now, the issue is that all of the neutrals are either hostile or potentially hostile to BD in one way or another (Scorned wants to get innocents killed, Fool’s goal benefits Cult/Unseen by delaying executions, Alchemist has little to offer BD and is [I think] a common false claim, Mercenary loyalty will shift if the person they’re protecting is converted [or was evil to begin with], and obviously Possessor and Reaper just want to kill everyone).
Neutrals are harder to come up with since they need to have goals other than “kill the other team” (we have two with a goal of “kill everyone” but making more of these would be detrimental to the goal in your post). In general I like the classes we have now (the Fool in particular was a clever twist to the game that I really appreciated), but we definitely need neutrals that aren’t just unaffiliated evils.