1. Clouds & (non)occlusion of plume(z-order?).
The particle system FG is using, sorry, sucks... it doesn't play nice with the effect and shader framework, yet there doesn't seem to be an easy way to replace it. This z-ordering mismatch happens for basically all particle systems (SRB exhaust of the Shuttle has the same problem with clouds).
2. Vegetation: translucency (Hawaii). Couldn't decide if it's intentional (to help blend in). Posting just in case.
Intentional - making the vegetation 100% solid looks very odd - in reality you can see a bit through foliage, and while not perfect, alpha-to-coverage generally is preferable over the alternative.
3. Aerosol: volcanic plume/condensation in vortices etc/smoke: don't normally take colour of sunlight after outscattering like clouds do in FG eg, eg? screen. Also randomly wondered if ALS lightsource @ ejected lava center of mass would work.
As long as ash plumes work with the particle system, we can't run custom shaders on the result like for clouds.
4. Volcano:disabling by UI toggle doesn't switch off. Plume particles messed by time accel(Just something I noticed). Test: Kiluaea, max activity. People that notice volcano entry in menu can't know which volcanoes are simulated yet without searching for thread (or release changelog I guess)?
I think the general UI toggle prevents new volcanoes from ever entering the menu, but an active volcano needs to be switched off in its own menu. The logic is a bit... odd, but then there was the requirement on the devel list to be scalable to a few hundred volcanoes, so for the three that are implemented, this seems weird.
I guess we'll just keep adding some and maintain a wiki page, eventually it'll make more sense. I hope.