They don't claim to bring new truth to the church. Their hope is to bring unchanging truth to a changed time. To do this, renewal movements take on the challenge to energize, challenge, redirect, and perhaps even redefine the church and what it does in this day and age.
Church renewal has a theological task as well.
Renewal movements have a responsibility to be faithful and consistent about the teachings of the gospel. After all, we're talking here about renewing a church that God has been working with and working on for two millenia. Yet it is just that faithfulness and consistency that will lead it into new strategies, approaches, and proposals. The churches may not be much interested in listening. They may get defensive, or support a new set of rules based on something other than the faith the apostles preached.