The only thing that makes preaching worthwhile to me is for Christ to speak through my sermon, because I don't like preaching enough to put myself through such a painful process for any goal lower than that.
On the other hand, when the goal is to preach Christ, when the passage is studied through and prayed through and practiced through to provide the venue for Jesus to speak to the congregation, then the process is worth the effort. The congregation figures out that the sermon is dead-serious business; pretty soon they begin listening for the voice of Christ. Eventually people invite their friends, because something important is happening at worship, as opposed to something enjoyable.
Speaking through the preached Word, Christ speaks to listeners personally, drawing them to himself for salvation, for repentance from sin, for comfort, for commitment to ministry. Every sermon, no matter how much exposition or story-telling it contains, must have as its goal Revelation 3:20: "Behold, I ...1