For a long time I have wanted a way to modify the symbology scale for polygon and polyline patches in the legend.
For example, if i have a large point symbol in the map, I can scale the point size so that it fits inside the patch size.

But it would be good to modify the scale of dashed lines and 'lines' / 'polygon outlines' if you have sybology that doesn't fit into the patch at the correct scale.
Here's an example of what should be a dashed line:

If i could scale the symbology in the legend, it would look like this:

This is especially useful if you have large symbols along the line.