I'd like to add my vote for this as well:
– color picker for various site elements (widgets, body, background, etc.) AND navigation menu

It would be especially useful for the navigation menu. Just having some nice color presets (green, red, orange, blue, etc.) to choose from would be great.

Because the current navigation menu color is built from a combination of a repeating nav.png file, plus a body_bg.png file that handles both current selection and hover over effects, plus CSS code for hover over and current selection underneath the png files, plus CSS code for the top bottom left right borders, it requires a lot of trial and error and it takes a very, very, very, very long time to change the menu color just once. Even the free Frisco theme has this “select a preset color” feature, and we dumped that theme to use BuddyBoss!

We only use text links in our footer area, but a multi-column footer widget area would definitely help us improve its layout and presentation.