Three systems of different age? that will explain it. Since years it is forth and back. When it is implemented people complain, when not implemented people complain.
Honestly it is one of the first things I look for and install on my xfce’s.
I know, you want to open thunar root for a easy (convenient) way for editing files.
So, in order not to anger the high priests, here is a better, still lazy and convenient way
to edit your files in the root directories.
Open thunar as normal user > Edit > Configure custom actions
…in the dialog:
Edit in Nano/Root
xfce4-terminal -x sudo nano %f
File Pattern: *
Appears if section contains: “Text Files” and “Other Files”
…and a nice red terminal icon. -Apply - done.
But careful, much power much damage.