Yeah I am a big fan of the Ephesians exhortation 'give no place to the devil.' Sometimes other things are going on when Pastoers fall. All our Churches have Paster's as primary leaders. That is tradition and does not seem to fit with the New Testament pattern. We do it because everybody else is doing it. The whole 5 fold Ministry is the pattern for leadership. If a Paster takes on the whole deal because of tradition and not God's appointment, he will sruggle and not be equipped for the task. The grace of God will not be fully there. I'm a teacher but I would not take on the entire leadership of a Church. That would be presumption and not God's leading.
The other thing is, it seems only a small % of the Churches have a proper understanding of the results of Jesus atonement. Though it is very clear in the NT. If you don't have a proper personal grasp on the NT's revelation of the new creation then you are going to be vulnerable if the whole Church is pivoting on you. as the leader. It is no small thing to take on the role of lone leader of a Church. A Pastor would need to be mighty sure God put him there. If he can't get confirmation of that, seek God for where you are supposed to be and move there quickly.
My point is tradtion and denominational doctrines that differ from the NT's teaching make pastors vulnerable . Of course some who are Apostle's or Prophets and God appointed leaders are often referred to as Pastors. The enemy knows the Word ,therefore we need to rightly divide the Word to win.