Here’s my conviction: singing is prayer. That’s the spiritual discipline that it is most like. And in the church, music’s primary purpose is to connect right feeling with right prayers. So, when you’re selecting songs to sing, the question you want to ask is if you want to pray a prayer of the people, or a prayer for the people. Occasionally, it’s good to pray on behalf of the people, but most of the time, you want the people to pray. So: you want the people to sing, and to do that, you need songs that can be sung by the congregation: not too complicated, or too far out of most people’s range.
How like speaking in tongues is a good worship song that nobody can sing: Is it doctrinal, rich, thick, beautiful? Good! But if the people cannot sing it, where is the amen?