Clouds,
I would love to add everything you describe to the Sicily terrain, however, AH is very limited in that regard. It's primary focus is as an WW2 Aerial Combat simulator, not a super detailed terrain generator. I am sure HTC wouldn't mind making the terrain model that detailed, if they could do it and achieve high frame rates on most of the systems people use. However, I think it will be 10 years before you see that sort of detail in terrains for MMPOL sims due to connection and PC limitations of the average user.
In AH, we have a limited number of tiles to use for terrains. For example, I could add snow to the top of Etna, but then I couldn't add the Magma flows. I also considered making Etna smoke, but many people have trouble with frame rates when there are alot of clouds and especially if we use the storm cloud layer, so I specifically avoided that.
Also as for fences, etc, there is a limited number of objects you can have on a terrain and fences aren't modeled, although the sides of a VH hanger could be used for large fences, but we simply don't have that level of detail available. Also, the resolution of the terrain is that there is a node every half mile, and although there are many lakes on Malta, we would only be able to use the pre-existing lake object as such and would still need info on where all of the lakes are etc.
