The system as it exists for training pastors does not ensure that he is prepared for the office. A man can be catapulted right into the highest position where he has no accountability, and have many character "issues" unresolved, that would have been worked on if there were a system of accountability whereby a person is better trained for that office over a period of time.
A person can be listening to the Holy Spirit and be waiting on God, asking Him to show them if they are ready to be used by Him, and then move out as they are led, and thus allow God to work on their character over a period of time before moving out. But there are those who are all too eager to get into high positions because it validates them, and they lack genuine, authentic closeness to the Father, and the character that is essential to the position that they seek. These people do not listen and they do not wait, and the system of the church that exists is all too willing to promote them anyway.
This is a sad truth that I saw played out with my own father, who now in his late life is left with seemingly no relationship to God at a time in his life when it would seem most desperately needed. He lacks what he needs even for himself, yet he "shepherded" a whole flock. It is so pathetic.