A tremendously long awaited layered material got me a bit overexcited so I made 2 versions of that materials gui mockups which, as I imagine, could be much more useable and fool proof than the one which is currently implemented. There's totally no need to copy vray's crappy and unintuitive VrayBlend material cause, imho, people which are used to v-ray and don't want any improvements should just stay with v-ray and not plague corona with their workflows ))
To the matter at hand - first mockup is based on modified multi\sub-object material logic and the second one is based on modified composite map's one. Both of those are quite familiar to most users and those for which those aren't a part of the daily work, usually don't need such advanced materials as multilayer anyway)) so I think that even given the differences with originals people will easily understand how to use either of those.
In both cases I've used material and map preview windows cause I think and I think many will agree that working on complex materials without those is a major pain, especially when one needs to tweak that material later on and by that time totally forgets which map\material was put where and exactly why or imagine some studio work, when different people work one after another on the same scene\models\materials and so on.
Visual representation in CoronaLayeredMtl material\map slots is a must imho - for instance just try to imagine how tremendously crappy and unwieldy would be afore mentioned multi\sub-object material if it would not contain those previews as it does now.
Both of those mockups are are of course pretty crude and can be made prettier, more logical, and simply cleaner looking but I think as a reference those will suffice for now, so people please do tell me that you think of those. Personally, I would prefer something similar to v2 as imho it is cleaner, more foolproof and much more understandable from the first glance, but of course that could just be my overexcited imagination ))