The discussions below on preaching, 3rd use of the Law, exhortation, etc., have also served to reinforce the connection in my mind between these issues and the need to do a lot of teaching from the pulpit.
I've not been out of the seminary long - just shy of a decade - but this is yet another issue where I have changed my mind pretty thoroughly...and reluctantly. One of the formative books for me in my seminary education was Forde's Theology is for Proclamation. Forde had his problems, to be sure: he was a universalist, did not subscribe to the Formula, and had no problem with women's ordination. But whatever his (significant) faults, this book forcefully and beautifully reminds us that preaching should actually do something, not merely be about something. We should preach the Gospel; not merely preach about the Gospel.
So in my early ministry a definite pattern emerged. My sermons were tightly knit, intentionally and individually crafted proclamations of Law and Gospel. The sermon was almost exclusively "preaching the Gospel" and I saved almost all of the teaching of doctrine, the "preaching about the Gospel," for Bible Class.
I love teaching Bible Class. I flatter myself to think that I am good at it. I love to get down into the nitty gritty of Lutheran theology, talk about the liturgy, dig deeply into a book of the Bible, etc. The expositional homiletic style popular in American Evangelicalism I find truly cringe-inducing. For one thing, I don't think it works well with a lectionary. I don't want to turn sermons into Bible Class. I don't want to be guilty of merely preaching about the Gospel and never preaching the Gospel. So I was very comfortable and very happy with the arrangement in which I preached almost straight proclamation from the pulpit and did almost straight teaching in Bible Class.
But as time wore on, especially as I stayed put in one place, the more I came to see the weakness of this arrangement. First of all: most folks just aren't coming to Bible Class. No amount of inviting seems to affect my numbers much. I have anywhere from 1/5 to 1/3 of the adults who were in church in Bible Class each Sunday. The number fluctuates not because of new people trying it out, but due to the weather.
Second, the more I remain in one place, the more I see how little of catechesis sticks and how little I'm actually able to get my catechumens through (especially the kids from families that choose not to utilize the Lutheran school). It needs constant, life long reinforcement.
Third, I began reading a lot more Reformation era sermons and Church Orders. I saw that the Reformation actually took place via teaching from the pulpit. I saw Luther preaching not exactly like Dr. Stanley on the radio, but not exactly like me and Forde either. I saw Chemnitz give instructions that the preachers should make sure that the people learned "something definite" from the sermon.
And fourth, and perhaps most decisively, I realized that many of the people were unable to articulate why doctrine was important, why it was good to be in this church and not that church, why the liturgy is a good thing and not merely a preference, why we practice closed communion, why we teach what we teach, etc. I was covering all that in Bible Class....but the majority of the people were not hearing it.
I still don't imagine that I have "fixed" my preaching in this regard. I try to do more teaching from the pulpit, even while I try to also keep Gospel proclamation in there each week. One problem is that I am acutely aware of my congregations' expectations when it comes to how long church should last. I have to plan to be very efficient in my presentation to keep church around 60-70 minutes. We can complain about that all we want, but I don't see it changing very fast, at least in my neck of the woods. Pastors who have tried to move their parishes to every Sunday communion have encountered the same limits and frustrations when it comes to time.
So, I think we need to be very intentional about doing more with less. One great idea I got from a friend and colleague of mine, Dr. Ben Mayes. He keeps notes on what doctrinal topics fit well which each Sunday's readings. Then he can refer to that list during sermon prep and easily cover a topic - and make sure that a full range of doctrinal topics are covered in the course of a year. I have his notes here somewhere....I should be more faithful in using them!