Thanks very much for the feedback! 🙂
In time we will be creating various specialized material nodes, similar to how it is done with the existing water and glass nodes (which are used internally to create dielectric materials).
So, these will be higher-level materials, exposing simplified sets of parameters, to make it easier/more efficient to create and work with plastics and so forth. The trick is defining them correctly, to give enough control, but not to clutter things with rarely-used parameters.