If there is a Traveller, I'd like to see a kind of Bureaucrat (not "Bureaucrat", since that name is taken already) who basically starts off as a low-level flunky, and works his/her way up to being a Vizier or Viceroy.
However, thinking about it, I doubt there will be a Traveller. With 25 Kingdom cards, and let's say 1 Victory Kingdom card, that takes up 252 cards, plus 25 randomizers. That leaves us with 23 cards left. These will probably be 10 Events, and 10-13 Landmarks, with the rest being blank cards. In order to accommodate a single Traveller, we'd have to lose 2 whole Kingdom cards to free up the 20 extra card space needed.