Us telling the Vigilante to kill and who to kill comes with some issues though. If we openly tell them this and they listen, they may kill a citizen and the mafia will know not to waste anything on that person tonight. They'll kill someone else. That'll immediately bring us to 11 players, 4 mafia and 6-7 citizens. If the trial goes poorly and a citizen dies, it's already game over. That's not even considered the possibility of a third kill ability. Then we gotta deal with potentially not knowing who died.
I just don't see the reward, or at least a reward that compares to the risk. We know there's a Vigilante, okay fine. To what end? What's the gameplan after? Openly choose a Vigilante target and a Trial target while watching the Jury every day?
I agree this is tipped heavily in the favour of the mafia so we have to take risks, I just don't see a big reward for a huge risk.