Im experimenting with appending the Blender glTF2 pbr material (which also appends the nodes) and my existing models material and so far looks good.
Wiped out the existing texture links during the append but doesn’t matter since you have to reassign the textures to the new pbr materials anyway. It did keep the original materials and the vertex assigned to the original materials so its just a matter of selecting the old materials and assigning them to the new pbr material.
Havent tried exporting yet, have to install the latest glTF2 scripts since old ones were not working for me.
I was looking at the bsdf stuff so I will give that a try also.
Materialize looks very promising once I figure out the asset pipeline.