When I saw the pre-release PMBOK Guide 4th edition draft, the new data models attached to each process caught my eye.
I liked the 3rd edition’s attempt to capture data and process flow. However, the approach was a bit clumsy, largely because it was done by knowledge area. To be fair, the 3rd does have a set of process group diagrams in Chapter 3 with a decent overview of the flow.
While the big picture view those diagrams provided was nice — versions of them exist in the 4th edition — mapping the data inputs/outputs by process is more rigorous and intuitive IMHO. I was OK with the boxes listing the data I/O, but the models are much more effective visual representations of the individual processes.
I’ve provided a couple of examples of the different approaches FYI.