Let's get one thing clear up-front: I work with, listen to and learn from a wide variety of software developers, but I'm not one myself. I'm a customer. I use, complain about and (occasionally) commend the tools developers build. Some of my best friends (as the saying goes) are software developers, very good ones, in fact. Many are specialists with PDF.
When asked, they agreed that the style and structure of the current PDF Reference simply isn't ready for ISO as-is. As noted earlier, today's PDF Reference isn't written in the typical language of ISO Standards. The Reference makes no differentiation between normative requirements, recommendations and statements of current practice in Adobe's Acrobat tool. It's hard to see how one gets PDF to an ISO Standard without undertaking quite a bit of this rather heavy lifting.
The current ISO PDF Standards, PDF/X and PDF/A, are both under 30 pages. Both address highly focused subsets of the 1,300-page PDF Reference 1.7. The ISO PDF project will dwarf those "miniStandards".
The necessary task of editing the PDF Reference in the timeframe Adobe envisions (12-30 months) seems likely to mean full time work for a small group of highly talented people. Will Adobe dedicate these resources? If it does, will anyone else be able to dedicate the resources necessary to keep up with them? But perhaps these are boring practical considerations. Let's look at the hummer.
The earlier iterations of the Reference were (to be plain) short and loose. Even the current 1.7 version Adobe is taking to ISO contains many ambiguities. Yet since it published the PDF Reference for anyone to use, Adobe bound itself to respect as many of the possible ways a PDF could be (mal)formed. And they are legion.
OK, so you want to stamp your document. Maybe you need to give reviewers some advice about the document's status or sensitivity. This tip from author Ted Padova demonstrates how to add stamps with the Stamp Tool along with related comments.