It'd be cool if we could click a color in the palette, change it, and if that old color existed in the current icon, then have it change every color to the new color in the palette like we used to be able to do.

For example, an icon uses the color #00FF00. We doubleclick that color in the palette, change it to #059600 in the prompt following the doubleclick, and for every color in the icon that equals #00FF00, change it to #059600.

It was so incredibly useful, especially when you're testing the color with a TON of icon states.