Here is an idea I recently had,

What if, you had a tagging system much like the color code system already used, that incorporated symbols or emoticons, that were selectable via a dropdown menu just like the color dots.

This way you could more easily see the general feeling of the song. I have a hard time telling the pastel shades apart from eachother on the little colored dots,

Perhaps you could even import your own emoticons or symbols,

I love Serato!