We need a balance of teaching and exhortation from different body members in order to be balanced. If we consider these problems we can understand why the New Testament does not teach us to have one pastor in each church preaching all the sermons, but rather a plurality of elders and meetings open for all so led to share their gifts. Maybe if the church format allowed for a 'multitude of counselors' we'd see less false doctrine developing in Charismatic circles. Another concern with our current system is that the preacher determines his own text. We think sermons teach well, but a preacher picks three points out of a huge text, quotes only a few verses, and preach on it.
Few preachers preach through the whole Bible systematically.
So many in the congregation never hear the verses. Nowadays we think of Bible study as something a believer must do at home. Historically, this was not the case. The printing press is only about 500 years old. Most Christians before the printing press did not have a copy of the Bible, and many people were illiterate.