What I think people are saying wimvdb is that the process is complex enough to rob many of the ability to use it. You shouldn't have to be advanced to modify something. basic, e.g. you can use the volume control but to adjust trebel and base, ya need an EE. 

It's a semantic quibble I suppose, but I wouldn't even especially call liquid, metal, skin etc. presets. They're really base materials. I'd call elephant skin or mermaid tears (and anything derived from or incorporating them) presets - but that's just terminology. Nothing's perfecr. Vue has a dozen or more water presets like 'channel water,' You can modify their color, transparency etc., but they're no controls like 'murky' or 'algae,' things that would be specific to water. With the proper scripting support, people could write plugins to cover all kinds of general or more specific materials. If someone wants to include a temperature variable in their water plugin so that dialing it down cause surface ice to start forming, great.

So, have a hierarchy starting with the base materials. You can have environmental water or beverages under liquids, and drill down to as specialized as anyone wants. Use understandable parameters. rough, dusty, stained, wet etc. If I have to guess what it does, it doesn't make the cut. The ability to easily link some parameters to external factors e.g. water gets less murky over time or the closer it ges to the camera etc. You can expose the constituent parts of a parameter e.g. twiddle the things that make up murkiness, but that should be an oprion, not the default.

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken