Indeed, the MSFS XML driven Visual Effects Editor is derived from previous versions, so for example temperature still works as a variable as the original system had been modeled to represent smoke, but an overwhelmingly fundamental change was made in that we can no longer compose the most exquisite effects simply by manipulating a few variables editing the .fx file with Notepad. I am talking waterfalls, tornadoes, plasma clouds, bullet tracers, etc. Presumably, the additional parameters of the MSFS VFX allows for an even greater variety of effect application, but after seeing so many "fires" modeled in 3d of all things, I've yet to be reassured in my presumptions.
FSX/P3D has a pretty good .fx editor. I think you have to activate the SDK to access the editor, but you can see changes in the effects appearance in real time. It is actually becoming difficult to find examples of the FSX style effect editor being used, quite common just a few years ago, but they seem to be displaced by MSFS information. Below is a screen of the FSX effect editor and below that is an image of an effect .fx opened in a text editor for manual editing. MCX also allows for visual feedback editing, however the render is significantly different from what is visible in the sim.