On occasion, I'll get asked why my sermons aren't more practical - meaning that I rarely take the time in a sermon to lay out precise steps for putting into practice a particular principle from the Scriptures. Certainly there are a number of guys who stand up in front of people on Sundays and are very successful in gathering crowds to hear them pass along very good advice about how to live. And while I think there's certainly a place for equipping people to live, I'm pretty sure that preaching isn't the place for that to happen.
My reason for thinking that has everything to do with hitting a baseball or tying your shoes. Which do you think woud be more helpful - to tell you how to hit an 87 MPH slider, maybe laying out the specific steps in tying a double knot? Or would you be more helped by me showing you with few (if any) words how to do both of these. My point being that preaching is simply not intended to be an environment for providing a 'life lab.' Such environments exist, usually in smaller groups or one-on-one relationships where dialogue and conversation can take place in the context of modeling, apprenticing, coaching and letting people go and do their thing. For instance, our church believes that the most effective environment for biblical applicaiton of the most precise kind is in our small groups where you're not dependent upon only one other person's perspective but are with a handful of people who can focus on your growth and maturity.
If our concern in preaching is the gospel - and it most certainly is - and if the gospel is always the proclamation of a salvation that has been purchased in full on the cross, then preaching must be far more concerned with telling that story and helping both religious and non-religious people see how this radical revolution called the kingdom of God is created by the massive transformation of the gospel. In that it is immensely practical - no less practical than laying out five steps towards a healthy marriage or three stages of biblical parenting. This means that preaching must focus its attention on what the gospel fixes its gaze upon - the good news of what God has done in the person and work of Jesus Christ. Preaching is not good advice; it's the heralding of the greatest story ever told.