However, Conan always still attacks the wizard or supernatural creatures he is afraid of. I generally dislike game mechanics which make a character automatically run in fear, as they really break the players control of that character.
So... I guess I'm deferring to people more experienced with the rules than myself. Is there a way to add Passion "Fear of the Supernatural" without making it crippling to a PC?
And you are absolutely correct that the main theme in Conan is of barbarism being more natural and strong, etc., than civilization.
The superstitious dread is often worded in a way of Conan seeing the truth, where civilized men cloud themselves with lies, disbelief, insanity, etc.
(I could have probably worded that better, but it's bedtime and I'm really tired!)