I don't think he's an extrovert, but agree on the Fe gone horribly wrong part. Hitler was quiet when not speaking in public, and seemed to prefer being alone. Further his Fe was quite clearly subservient to his insane, fantastic Ni grand vision.
I think I know the most evil NFJ since Hitler though... My friend's dad is a high-ranking executive, an INFJ who leads using Fe (though he's managed to combine Fe, Ti and Se into a passable imitation of Te), and... bankrupts Indian companies for a hobby.
Before you say anything, no, this isn't a Paris Hilton situation.
The guy's kid (my friend) was actually the one who suggested his dad may be Fe/Ti as opposed to Te/Fi. From what I know of the guy I'm inclined to agree.