I would like to have a new feature for layers and layer groups. You can already set layers to greyscale in the layer manager. An addition to that should be that you can adjust the transparency with a slider. This way you can push some layers visually to the background. Examples could be the set layers (or the whole set group). Also if you can place a floor plan pdf on a layer and make that layer more transparent, that could help a great deal in making layouts and cad views easier to read. It could either be truly transparent or just more desaturated colours.