I give you ...
Screenshots to follow, but in summary: Humans get 275 rep for the Champions Writ hand ins, the diplomacy talent works on them :))
Also, you do get rep for the quest to become champion as well!
That means I have 6 totally worthless Champions Writ's as I am now exalted with all 5 home cities.
Unless you can hand them in for Argent Crusade rep? Anyone know?