layer display palette on the left sidebar
or other always-visible GUI enhancement that allows real-time layer display selection without blocking other actions, without requiring multiple keystrokes or clicks, and without taking up additional space on the desktop; could be fulfilled with keyboard shortcuts to toggle display for each layer
Gary Pinkerton commented
I refer to Overlays and Parcels a lot while maintaining a project with the route of a historic road. The layer visibility box is too small and required too much scrolling. Enlarge the window or rearrange it to allow easy access to options to quickly turn layers off and on.
Bill May commented
See in this forum "Visible (with single-click) listing …" for a single-click approach to viewing the show/hide status of the frequently-edited layer types.
See in this forum "Quick way to review the Show/Hide status of all sublayers in a large Project"