Quote - People already think VSS is a shader, and you don't want to have the shader on the same page. Fair enough, though I still wonder about that... I tend to think you're bucking something that you're never gonna shake.

i think you think way too small.  no one will think that when they use it to apply leather, linen and metal to the appropriate parts of a Luthbel outfit.  or easily retexture a Stonemason set.  Stonemason makes brilliantly compact UV maps, but his stuff is loaded with material zones.  or even better, use a Stonemason set and Davorama set together and control their metals, stones, plastics and lights with one interface. or control several pieces of P.I.C.K. with one application. 

i'm hoping and wishing for material packs for those types of surfaces, but an easy way to handle them all would do just fine.