Rick Jelliffe on designing XML Schemas in a way that support parts which frequently change

Hi Folks,

Earlier this week Rick Jelliffe casually inserted into his message a profound statement regarding how to create applications and XML Schemas in a way that support parts which frequently change.

I am trying to understand Rick's statement. 

I have many questions. 

Here is my summary of Rick's statement along with my questions:

http://www.xfront.com/Rick-Jelliffe-on-Designing-XML-Schemas-in-a-way-that-Support-Parts-which-Frequently-Change.pdf

Would you take a look at my summary and questions please?

I suspect this issue is relevant for many people on this list.

/Roger