If the leaders are not comfortable neither will the congregation be. It may feel awkward to lose a sense of control over what happens in worship. Then there is the question of when in the service to sing a new hymn or learn a new arrangement of a psalm. I have over the years conducted surveys where I ask the congregation to list their favourite hymns. It is from this list I draw when I want to balance new with the old.
Congregations are often resistant to changes in worship.
It requires real effort to learn something new. Choir directors and organists will need the support of ministers as they lead the way. The minister can support the musicians in their teaching role in a number of ways. First, time is necessary to learn new music. This requires planning ahead.