The ability to set different border colors on the same element (e.g., red bottom border, all other borders are gray). This is a minor request but would come very handy, especially in the context of Components as it will allow linking a specific border color to a Component setting.
Current work around is applying the color via custom CSS (but this cannot be linked to a Component settings AFAIK):
border-top-color: xxx;
border-right-color: yyy;
border-bottom-color: xxx;
border-left-color: yyy;