Temperament
tk: according to http://keirsey.com/personality/nt.html, Rand would be an INTJ. (And you've a typo s/F/T/.)
tk, faassen: According to that same site, when depressed (like now) I'm either a "mastermind" (Eisenhower, Rand) or a "fieldmarshal" (Gates (!), Thatcher). And when not, add: "crafter", "promotor", "inspector", and "supervisor".
Oh, yeah, and I'm also an Aries and a Dragon. ;-)
GUP
I think personas [sic] are a gimmick. They're a way to get programmers to think about the things that, in my experience, in programming classes they're taught to think about and detest thinking about. They're a shortcut around rigorous design. I never met anyone who liked drafting a flowchart. I hope they'll be an effective gimmick for GNOME.
Part of the trouble I'm having with a design document is the persnicketiness of some people. You can ask, "Does the application allow the user to create something?" and get the response, "Yes. My application allows the user to create a device state." Try to narrow it down: "Does the application allow the user to create a document?" "Yes. The document which is the permanent storage of the device state." If you actually manage to get a precise question: "This document is too long. I'm not reading it."
Another thing bugging me is that people make a living off of this, or at least get a degree. I doubt I'll be doing either.