It would be great to be able to modify the transparency of a symbol in ArcMap. Specifically to address the issue if there are several points stacked upon one another. It would be nice to have a symbol that much like transparency, would be transparency of the fill color itself. For example if the color was red, a slider more transparent would mix red with clear, so you could see through many stacked dots. Example of what I mean is attached. The picture "ArcMap Example" is the standard now, and the picture "Spotfire Example" is a picture from a competitor's software. In this picture, this is exactly what is desired. The deeper colors, red for instance happens because more and more dots are stacked upon one another. It also allows the user to see the other colors that may be in the same exact spot.