Could you consider adding the ability to add arguments to the Run Shell Script action. To keep things simple you could just pass the argument string to the shell exactly as entered. Adding variable and device value substitution before passing the string to the shell would be a nice plus.
I.e.
Full path to file on server: /usr/local/bin/mycmd
Command args: -x %%d:123456:onOffState%% -y %%v:654321%% -z "embedded spaces here" 1>/dev/null 2>&1 &
Alternatively, you could add a checkbox: Execute in background [] and add the 1>/dev/null 2>&1 & for the user
Having this ability in the Run Shell Script action would eliminate the need for embedded AppleScripts to perform essentially the same thing.
Thanks.