Not sure if this is still an issue for you, but I found this workaround helpful. I created an input box, since Autodesk doesnt support this iProperty at the moment. Function is basically the same as if the iProperty was loaded into the form.
For us, the revision description box is linked to the summary contents iProperty, so you might want to change the prompts that display to your users.
1. Create External Rule with below code:
iProperties.Value("Summary", "Comments") = InputBox("E.g. ISSUED FOR CONSTRUCTION", "Type Revision Description",iProperties.Value("Summary", "Comments"))2. Load External Rule in Global Form.
3. User needs click only 1 button, preloads current information if the user wants to keep it, but allows user to alter it if different.
Only issue is getting all users equipped with external rules, but if you are running global forms, it should already be manageable. I find vault helpful for distributing/updating global forms and external rules across a network of users too.