I find myself slightly bemused by this whole subclass. IRL, part of my work involves studying the effects of fires on forests. And wildfires naturally come in several flavors. There's the big stand replacing fires like we've seen in Yellowstone (in the 80's) and occasionally in the northwest. Big massive conflagrations that wipe everything out and herald the beginning of a new cycle of forest development. And these only come very occasionally (maybe a century or two in some cases). Then there are low intensity surface fires-- like you historically got in the Sierra Nevada of California-- that are much more mellow, burn off the surface fuels and occasionally torch a tree. These happened much more frequently, maybe every decade or two.
In both cases, the occurrences are 'natural' in the sense that in the particular forest and climate those fires happened on their own and the systems are adapted to them. In California, we started putting out all those mellow fires for about 100 years. Fuels built up and now we get much bigger conflagrations (this is in the mountains, coastal Cal aways had big conflagrations. different system).
Anyway, a lot of work in recent decades has been putting fires back into these mountain forests with controlled burns.
This is a long ramble to say that fire is an interesting and complex thing on the landscape. When I read the wildfire subclass I read it fully expecting to pan it ecologically. But they kept it so generic that it wasn't specifically 'wrong'. And now I just don't know what to think.
Which is a long way of saying, knowing too much about a particular thing sometimes makes one completely useless for providing playtest feedback for a fantasy game.
AD