I'll go first...
Draenei have, since the corruption of Archimonde and Kil'jaeden, been on the run from the burning legion. Many of their race have fallen over the millenia in this chase. I propose the new Draenei racial be based on the spirits of the fallen and be called, for lack of a better name: Strength of the Fallen.
My idea for this racial would work somewhat similar to the Darkmoon Card: Greatness and Death's Choice/Verdict...however obviously a smaller version
Strength of the Fallen: Increases your greatest stat by 3% for 12 seconds (3% at cataclyms levels should be a rather large amount of str/int/stam)
Or, to further integrate the mastery stat it could increase your mastery by 5% or some amount that's balanced with the other racial talents.
Anyway, that's my idea for a new Draenei racial, what ideas (hopefully rooted in lore) would you have for your own favorite race's new racial?