If you see the church as a “vendor of religious goods and services,” preaching will tend to take the form of life lessons and religious self-improvement (there are both liberal and conservative forms of this).
If you see the church as a “conservatory of biblical truth,” preaching will tend to take the form of verse by verse exposition or in-depth exploration of details and theology of biblical passages (this is primarily a conservative phenomenon).
If you see the church as a “spearhead of social change,” preaching will tend to take the form of social analysis and rhetoric to motivate to action (typically this is a liberal phenomenon but in recent years conservatives have begin preaching this way with a vengeance.)
In my opinion, none of these visions of what church is adequately captures the biblical dimensions and mandate of church. Thus, their views of preaching and the sermon are also inadequate and misleading.
Further, within the dynamics of North American religion, these inadequate visions of church and preaching are further disemboweled.
If our words lack corresponding deeds, as has sadly too often been the case, few care, even in the church, to what we have to say.
If our words stand alone, as is typical in churches here, we doom ourselves to relying on the least effective of all the ways we receive and retain input, especially if we do not practice a regular, i.e. weekly, Eucharist and regular reminders of our baptismal calling.
If our words are misdirected, that is, designed to an end that does not align with the church’s authentic nature and mission, they are so much wasted breath.
If any of these conditions afflict your church, then in this setting and with the way we envision the church and its preaching, the sermon can only be deemed the least important and effective moment in the church’s worship.
This is NOT to suggest that preaching is unimportant or ineffective at all! Rather it means that both church and preaching need a drastic overhaul in our time and place to recover their vitality.
P.S. This does not mean that God cannot use the church and its preaching to do his work no matter how far it has drifted from biblical dimensions and mandates. I am certain God has and does do just this. That God can use whatever we offer him, though, does not mean that he does not want us to pursue greater alignment with those dimensions and mandates for more faithful and effective practice of the way of Jesus.