Mafia: general discussions.

Immunity to chat spam isn't a good solution, I think that's pretty obvious. The fact that you wrote two hundred messages in a day shouldn't give you any significant advantages over other players who have different time zones or simply don't have that much time.
And it's impossible to effectively assess a player's usefulness because assets are usually killed first, and in the end, it's not them who survive. Besides, a person might not write anything for almost the entire game, but still solve three clues and figure out all the Mafia members.
Regarding necromancy and resurrection. I'm FOR such a role. There's nothing particularly cool about it, the only thing is that we need to come up with a good mechanic for this ability or just make it a one-time use for the entire game.
As for immunities, leave everything as it is.