Just answered a post and considered a few additions to the swatches panel.
When right-clicking on a colour fill swatch you have the option to Make Global effectively changing a fill colour to a global colour, but, once a colour has been converted to a global colour, that global colour should have its own context menu that would include...
Make Global Spot
Make Global Overprint
Revert Global (this would revert the colour swatch back to a global fill that can be used to change colours within a document en masse)