I've come up with a pretty simple way to enable multiple layer symbology all at once using the toolbox linked below. After you've added this toolbox, drag and drop the single symbology layer and then drag and drop all the layers you want to apply the symbology to (targets). General rules about matching geo-type (lines, points, polys) likely apply here. Once the tool has run, it will appear as nothing happened. Refresh your display (F5) - display will update with matching symbology. Click on a layer to view it's properties and click "OK" and the TOC symbol will update.
Download the Zip file for the toolbox here.
Here's the script if that is easier:
# Script arguments
Target_Layers = arcpy.GetParameterAsText(0)
if Target_Layers == '#' or not Target_Layers:
Target_Layers = "LayersToBeChanged" # provide a default value if unspecified
Symbology_Layer = arcpy.GetParameterAsText(1)
if Symbology_Layer == '#' or not Symbology_Layer:
Symbology_Layer = "SymbologyLayer" # provide a default value if unspecified
# Local variables:
Output_Symbology = Symbology_Layer
# Process: Apply Symbology From Layer (3)
Hopefully it works for you too.