Hi Lyle,
I am not aware of an option to escape the JSON data output by the list run property set command. I have forwarded your request on to our engineering team for comment.
In my tests the quote characters in the JSON snippet for the Run Property Sets are not escaped in the data output by the run property set list command - and, as you state, the create/replace run property set command expects the quote characters in the JSON snippet to be escaped.
As an aside, if the value of a run property set includes quote characters, the quote characters are being escaped in the output of the list command.
Regards,
Adrian