Hi Graham,

The PMBOK Guide is only that: A Guide to the Project Management Body of Knowledge.  You've hit on its main value; it provides a common language, a set of principles, and a base level of knowledge.

Too many folks don't understand that it is only a guide, so they follow it slavishly.  In fact, all you get w/ PMBOK-compliant approach are basic (and generic) standards.  To achieve maturity, one must execute against those standards, manage against them, then optimize based on your experience.

Best, Paul