I couldn't take it anymore :) and put the revised article into the UIG:

https://kantarainitiative.org/confluence/display/uma/UMA+Implementer's+Guide#UMAImplementer'sGuide-why-the-patMotivationsfortheDesignofthePAT

Thanks to the commenters so far! Happy to take other suggestions/improvements.

Eve Maler
Cell +1 425.345.6756 | Skype: xmlgrrl | Twitter: @xmlgrrl