FW-200 fire origin is bizzare

[JVM]

No I do not think so. Even in a small fire or an evolving fire, the flame is always much brighter than the background and "hides" it effectively.
Do not forget than from this brightness standpoint the (fuel related like in the Fw, presumably) Wellington flames are spot on.
On th eother hand shapes and smoke transitions are very good on the Fw...I am pretty sure tha Luthier is simply showing a lot of possibilities and they have a pretty good idea of what is right!
Generally speaking, all airborne flames are too bright to see behind; they maybe of different sizes or colors depending of what is burning, in which quantity, and what are the aircraft speed and altitude (the latter ones are very important, but probably not yet simulated in SoW, and probably not before long...).
The smoke is another matter entirely.

JV