Michelle, you've interestingly lifted up the impression that the prophetic books give that only certain people can speak for God while the wisdom books present God's wisdom as self-evident to everyone. Even if the *content* of both books address everyone (the prophets are claiming that it is the people's actions that have prompted God's response), the *style* differs.
Most of the posts I've read so far seem to prefer the wisdom literature, seeing it as somehow more universal, even democratic. That leads me to reflect on whether religious leaders actually believe that all people have equal access to the knowledge of God based on their own experience. If we really believed that, would we teach and preach from a religious canon? Would we preach at all? Even of we don't call ourselves prophets, might we also believe that God can speak through individual voices such as that of Amos and Isaiah and us?