Being able to add more than one shader to a material wrapper would be very useful I think. It could look the same as a blend shader setup where you can add more than one “layer”.
If the goal is to control multiple objects (with multiple materials) at the same time with one wrapper, you can already do that by just assigning a VRayObjectProperties to the objects.
Each object will keep its material, and the obj. properties will be applied to all objects. The obj. props node has all the wrapper attributes. We have both just to allow control at a material or object level for convenience.
I’ll need to revisit the scene I had, but I had obj props already doing something in the scene, but I needed the same set of controls again on a bunch of stuff. I’ll report back once I find time to dig into the reasons I had for this.