Good Biblical and expository preaching is best done by appealing to all aspects of a person – mind, volition and affections. In fact good exposition of a text of Scripture must make appeals to both mind and affections if one is to see a volitional change toward obedience to God’s commands at all. Jonathan Edwards said that the use of affections in preaching should be in proportion to the passage you are preaching from.
As I have read Jonathan Edwards, I was often stopped short by Edwards’ wisdom. Constantly surrounded by conflict, and often facing people who sought to undermine his ministry, Edwards had every opportunity to reflect on the task of a minister. One of these conflicts involved the question of whether sermons should primarily enlighten the mind or whether they should primarily stir the affections. Charles Chauncy, his opponent in this debate, believed that “an enlightened mind, and not raised affections, ought always be the guide of those who call themselves men; and this, in the affairs of religion, as well as other things.” Chauncy, as with many men of his day, believed that the affections were closely related to the passions of one’s animal nature and needed to be restrained by the higher faculty of reason. He wrongly concluded that the intellect was on a higher plane than affection.
Edwards disagreed, teaching that one could not neatly separate the affections from the will. Both the intellect and affections are fallible and unreliable, he insisted, but both are given by God and ought to be exercised by the Christian.
Good Biblical and expository preaching is best done taking the 1 point of the passage as the 1 point of the sermon. Then all other moves in the sermon (Sign Posts) are either an explanation, illustrations, applications, argumentation or celebration. Repetition is good for peaching for the ear instead of the eye. I agree that if you have a good idea then repeat it in relationship to your main sermon point over and over and over again.
So in my humble opinion, my education, experience, and study of scripture leads me to embrace Extemporaneous Preaching as the best style for most preachers.