Following on, if you do need to redesign the community interface, inform everyone first. Explain why you need to do it and the benefits of doing it.
Take your community through the entire design process. Show them the same screenshots and templates your designers show you. Listen and respond to their concerns.
Let members participate in the new design. Use some of their suggestions and invite important members to test the community before you launch. Perhaps even let them write the copy for each other?