Add a Spot Colors channel to the Separations Preview window
Add a "Spot Colors" channel to the "Separation Preview" window. Like you have in Acrobat. See screenshot attached. This will make toggling through the spot colors a LOT more easier and efficient. Then having to turn on and off each spot color individually.
Kevin Prutzman commented
This is a suggestion for the "Separations Preview" panel in Adobe Illustrator. Please add a "Spot Color" box to turn all the spot colors on or off in one click. (Like you have in your Adobe Acrobat "Output Preview" panel or with the CMYK box in Illustrator.) Having to deal with a lot of spot colors in a file becomes very time consuming having to click off and on all the spot colors one color at a time.