Is there any difference in editing a structured document which is intended to ultimately be text for presentation and reading, versus a structured document which is describing requirements for code or a storyboard for a design?
Do these different end-results change the collaborative environment?
I would think yes. Structured editing is tough because of the interaction possibilities. Think of it in simplistic terms "add words to paragraph" at the same time as "remove paragraph." What do you do?
With text presentation and reading, you are ultimately limiting the number of things that can be seen that way. Though, you can of course expand your entity list to include more and more things. Headers, lists, sections, chapters, paragraphs, etc.
That is to say, I think this is already difficult for structured text. Adding more structure, in the forms of "requirements section" and such just compounds on that complication. I'm not sure it adds more.