I agree with your original request. Color by tag per edge or face would benefit some stuff.
I need way more flexibility than this though, so we can have more presentational power in SketchUp output.
Layout is slow and cumbersome to control if you have to go back and forth between SU and LO. Defining every stylistic feature in SketchUp allows for way more power to us users, as not all work finishes in Layout: animations, images, vector graphics…