At the moment when creating complex Map Templates you have to in effect have two sets of symbology. The Representation Markers for the map face and then the Fill, Line and Marker symbols for the the marginalia. (Sometimes it is not desirable to use dynamic legends.)
At the moment there are two distinct and mutally incompatible methods of creating symbology in the style library and you cannot simply copy a Representation Marker to the Marker, Line or Fill symbol catagories so you in effect have to redesign the wheel to get these features as Symbols. Although it is possible to "save" a Representation Marker out as a Symbol, this then becomes uneditable so is not always the solution.
I would like to see Representations to not only be available for use to symbolise features on the map face, but to be able to be reused as symbology for elements in the layout view.