I requested it in JIRA a couple of weeks ago.
The current workaround I’m using (my situation involves radio buttons) is to have an additional radio button with a value set to "(Inherited from parent)==@INHERIT"
That way, when the default value is set to @INHERIT it will precheck the Inherited from parent radio button by default. Not the most UX-friendly solution, but an improvement over showing @INHERIT text to end users (the equivalent in my case was not selecting a radio button at all, making it look like they had to make a choice).