I’ve been toying with the idea of creating new NPC classes. Most of those I’ve thought about (such as the Bureaucrat) can be easily modeled with the Expert.
Two that don’t fit, though:
I’d like to see a Hedge Mage class that does for the Wizard what the Adept does for the Cleric. This class would also be good as an alchemist.
I’d also like to see a Thief class. Take the Expert, specify its skill list, switch its good save to Reflex, and add a few weapon proficiencies (like the sap). Alternately, to make it more of a Cutthroat/Thug sort of criminal, take that and drop it down to four skill points per level and add in sudden strike at one half the rogue’s progression for sneak attack.