If they have ONE leader, they are not following the will of God. God NEVER intended one person to lead anything.
1. He sent out in twos
2. He placed multiple men in charge at jerusalem (john james and peter)
3. Paul understood this as he refused to go on any trip unless he had a fellow partaker of the gospel with him.
There are reasons. We need checks and balances, a man, no matter how mature he is in Christ, Can get proud, and try to add his beliefs to the truth, if that man is not tested and held accountable by another person equally in charge, then we have no checks and balances, and no one to stop the new doctrine, which is not from God, from being imposed on that church.
This is what happened with the catholic church. The pople is seen as God, thus no matter what he says, everyone take him at his word that it is from God.