"I wouldn’t start from here"
Have you ever been told, when asking for directions to somewhere: “…if I were you, I wouldn’t start from here “?
If you have a 300 page, UML-filled mega-document, and you want to get this approved by your business stakeholders… well I wouldn’t start from there.
At best, you’ll take days or weeks to explain it to them, then spend more days and weeks processing their feedback and creating an updated version. Then do it all over again.
At worst, your document will be approved without comment, and everyone will rejoice at your brilliance, and the project will go forward – on foundations of sand. Because nobody read it, but they approved it anyway because of lack of time, fear of holding up the project, or lack of understanding of the content.