I’m gonna throw out there that the keyword you’re looking for in guild is witch hunter.
there’s a lot of actions that punish poor positioning or grouping together coupled with the burning condition not ticking down anymore means one action or more needs to be taken to deal with it.
Burning gets around a bunch of defensive tech too which can irritate an opponent and even if they don’t mind the one or two points of damage from a mildly on fire model, there are quite a few benefits you gain (or constraints put on their options) from them leaving the model on fire as well as some quite high damage actions like Sonnia’s summon action that can tilt an opponent.
in addition to this the crew can put an absolute massive amount of damage even in the absence of the fire condition (sonnia, thralls, Samuel) and isn’t short of movement tricks either which can frustrate attempts to pin down anyone other than sonnia herself.
oh and most of them have shielded or can use soul stones or have solid effect when they die and don’t leave markers.