I think the default shader could use a debug colour. Often I am working procedurally, and textured objects don't support this, so I have to rely on spot rendering, or RTP. But solid default shader colour works fine. So if I could set a debug colour, I could at least differentiate shaders easier.
That's not a bad idea at all.
In Blender I assign bright primary colors to all materials. These can be used to assign material IDs in Substance or Mixer, and to check textures as they are reconfigured in Terragen. It's worked pretty well in the long run.
Yeah see, that is sorta what I do. It makes it a lot easier to differentiate parts and textures. I started doing this to export to TG so I know what part is what when I am too lazy to name the parts (I don't like that when I fix a model in MeshLab and open it all my material names are gone and replaced with numbered "Material"...