It seems to me that all preaching should aim at response/repentance/transformation. God’s word should be served up in such a way that people can receive it and act upon it. Of course, this whole business is easily manipulated, and some preachers have abandoned inviting people to respond because they don’t want to come across as hucksters or insecure megalomaniacs. But if response isn’t built in to preaching, it sends the subtle message that no action is needed. "You now have more facts than you had at the beginning of the service, so now you are better off. You have done it – your Sunday duties are over. Go home and watch the game."
I read somewhere a quote by Rick Warren, who said something to the effect that if you’re not preaching repentance, you’re not preaching. Preaching is proclamation that demands a response. When Jesus came by and said "The kingdom of heaven is at hand," people knew that had to spring into action in order to get in on things. The Pharisees knew they had to spring into action to put a stop to things.
Maybe part of the problem is that preachers have spoon-fed people for so long that we have accidentally learned that, really, no action is required. All that’s needed is the gumption to get to church, and even that is optional when you can download the MP3 later that day. The expert has done all the footwork for us, distilled the Scriptures down to three alliterated points, which we can memorize easily, and now that we know it, that’s all there is to it.
But of course Jesus did things completely differently. He was intentionally vague, some would even say obtuse. He asked questions that probed the depths of motivation. He was remarkably circumspect when it came to explaining things to people. Basically there were 12 people who got things explained to them in plain language, and the rest just got their appetites whetted with Jesus’ say-it-and-wink parable-bombs. Maybe this is because explaining everything only helps those actively involved in discipleship and mission. Maybe the larger the gathering, the more vague and "salty" our preaching needs to become. Maybe preaching on large scales is more about awakening hunger than force-feeding people.