As far as as I know, all other buildings, farms and mines have a specialty that goes with them. Even the Barbershop looks for "The Art of War" when you are assigning someone. But not so with the Vicar. You can't use the academy to train them to be better at their job and they don't gain any skill at it. At least "The Art of War" would fit as it is also the specialty for the foreign office and barber, they are two jobs where you have to deal with other people's problems.
My guess is that you can (only) select i oversser with Spiritually Inclined ability - to be a Vicar, besides that he can't be "upskilled"
