Do your diagrams, design docs, and position papers not vary in the clarity of their presentation or in the wisdom/simplicity/fitness-for-purpose of the ideas they convey?
Indeed, they vary. The larger point is we still get a lot accomplished/communicated and done because of a common underlying methodology. I don't have an answer for what that means when adapted to the software field. Its going to be a soup of many things - coding guidelines, BDD, TDD, modular programming, etc, etc. I'm sure there are brains far bigger than mine already working on this, its not really an original idea in that sense.