Your sermons need to have one main point. There may be sub-points, and there may be supporting points, but there is [or should] only one main point. If your sermon has more than one major point, the people will tire of your message and not be able to remember what the sermon was about. They will subconsciously attempt to determine the main point. When they realize that your sub-points are overpowering your main point, they will either give up, or grab hold of one of your sub-points and assume that is the point of your message.
I was listening to a preacher the other day who had a pretty good style of delivery. While his style was good, his content was all over the place. The people had no idea what was important and what was not. Someone told me that they thought he was a good preacher, but there was something that the person could not put his finger on. that something is why it was difficult to listen to him. That something that was problematic about his preaching was that he had too many minor points that competed with the major point of the sermon.
If you have one point in your sermon, the people know exactly what the sermon is about. The preacher knows exactly what to put in the sermon (only things that support or supplement the guiding point). And an added benefit is that the sermon has a tendency to end at a decent time. If you want your people to know what your sermon is about, only preach one main point per sermon.