The past decade of local church ministry has taught me that big and small churches face similar problems, but for entirely different reasons. One example of this is the failure to address vocalists or musicians who have great talent, but a terrible heart condition (or even worse, theological beliefs as structured as a bowl of pudding).
Small churches have difficulty with this because they consider themselves to be a "small gene pool" and are nervous that if certain heart issues are addressed, that the volunteer may leave, which will lead to the overall disintegration of the music ministry. I have known destructive people that have held a vice-like grip on a church ministry simply because the leadership didn't address the issue for fear that the ministry would be destroyed.
Larger churches have this difficulty because they are under enormous pressure to perform and thus the need to recruit top talent to perform for the large group often overrides the value placed on the heart condition of a single individual. I have known megachurches that have put non-christians on their platform, to lead the congregation in worship, simply because they are talented individuals. Talk about a total failure of the heart! How can someone lead the people of God, to offer their praise to God, as an enemy of God? That would be equivalent to a member of a terrorist organization leading American troops into battle against their own terrorist organization!
The most important characteristic of any musician, of any Christian, is his/her heart toward God. Human beings usually see and hear the external only, which is usually very polished. However, the Bible is clear that God looks at the heart.
It is my prayer that every church, both big and small, will not position leaders based on talent, but rather on a heart for God and a dedication to the truth of God's Word.
But the LORD said to Samuel, "Do not look on his appearance or on the height of his stature, because I have rejected him. For the LORD sees not as man sees: man looks on the outward appearance, but the LORD looks on the heart."
~1 Samuel 16:7