When the Arsonist settings: "Target always dies" and "Victims target dies" are both on it often happens that the arsonist burns himself. The arsonist needs luck to survive his own fire.
Thats why the setting "Victims target dies" should be changed to "players who visit the victim die" (making the victim like a vet for one night).
With the new setting the arsonist cannot accidently burn himself and a douzed doc cannot use his "heal" as a weapon to kill a player.
The Kill/Night would be roughly the same (same when the target does not know if he was douzed).
It would also make sense because the victims house is burning and players who will visit that burning house will die.