I would like to be able to easily swap the value used for a symbol class from the symbology pane without having to add the new one, recreate the symbology, and then remove the old one. Being able to click into the value box and just replace it like you'd rename a label would make this little shuffle a lot quicker and easier.
For example, my dataset has changed so that what used to be 'Exterior Housing Rehab' is now 'Exterior Housing Rehab Focus Zone.' I have to go fetch that new value, symbolize it, and remove the old one -- there's no way to just switch it from here; the 'Value' column fields are not modifiable.