There's no theological reason why, except that by small and simple things shall great things come to pass." 
 
Jesus called fishers, tradesmen, and craftsmen to be his apostles, not Pharasees or Sadducees. The idea there, I think, is that God can show that it is by His power (not by intellect) that His work is done. 
 
I have seen church leaders who were simple, everyday men do miraculous things in church leadership positions. 
 
The church tries very hard to develop leadership in the lay ministry. We have our young people to go to seminary and institute, we enroll everyone in Sunday school and gospel doctrine classes. We give away thousands of books and encourage members to study them. We want everyone to become a gospel scholar so that when they are called to serve in a position, they will be ready to do so.

Christ did not call theologians but fisherman and tax collectors. Christ was not a theologian but a carpenter.  
 
Neither was Adam, Noah, Moses, Abraham, Isaac, Jacob, Saul, David, or John the Baptist.  
 
God does not call theologians (well actually he does if such be his will LOL) to the priesthood he calls who he chose before the creation of the Earth as his predestined leaders.  
 
Theologians have a lot of scripture knowledge and that is important but knowledge does not make someone worth of holding the Priesthood of God.  
 
The Apostle Paul told the Hebrews that "And no man taketh this honour unto himself, but he that is called of God, as was Aaron." (Hebrews 5:4) Knowledge does not prepare in anyway someone to become authorized to act on God's behalf. Nothing a man does or studies prepares him for the priesthood.  
 
Only the calling of God determines who is prepared to hold the priesthood this calling comes through the living Prophet and his appointed delegates.  
 
Look at Judaism for a great example Rabbis (teachers of the law) are theologians they have not priesthood power or office whatsoever though.  
 
Only those ordained by God are able to officiate on his behalf and God is not a respecter of men or the knowledge of men.  
 
He calls who he will and does mighty works through the least expected persons! Look at Moses a man with no theological knowledge that had a speech impediment and was not considered by anyone important was the greatest Prophet in the history of Israel.  
 
Saul a lowly young man of a the Tribe of Benjamin (which was one of the lest important tribes of Israel)was called as the first King of Israel and David a lowly Shepard Boy of Bethlehem with the might faith in God to slay giants was called as the King of Judea.  
 
Jesus Christ was born in a stable to an woman unknown to the world and raise as a carpenters Son yet he is the Only Begotten Son of God!  
 
God does not call his leaders and priests based on there theological knowledge, he calls them because he know the hearts of men and only needs a devout soul to part seas and throw mountains into lakes! 
 
 
I hope my answer helped you understand why theology has no impact whatsoever on someones calling from God.  
 
I appreciate the question and hope my answer helped you!