When you are deep into your own story, your mind has hard-wired all aspects of it in one complex mesh network. Everything is related to everything, everything is connected. The upside: you are the expert and know what you are doing. The downside: it is extremely hard for you to explain your idea to someone who comes in cold, without the bits of information, and without the connections between them.
After I return to my office after a client briefing, I usually open a blank piece of paper, take a pencil, and jot down the big ideas I heard in the meeting, after I have given the brain to calm down in the 30 minute journey back. No worry about story lines, no worry about structure, no judgement about what is detail and what is a big message, and no going back to my meeting notes.
These thoughts often become the core building blocks of the presentation. These are the points that I want others to remember when leaving a meeting.
Many people get to this point, they figure out the key messages of a presentation but make the mistake of communicating them in an overly simplistic, or minimalistic way. Just writing "the competition is not flexible" as a big, minimalist statement in a nice designer font is not going to make it stick. Many times, proven/showing these high level messages actually requires going into some depth.
So, a good presentation does not dumb down content. It unravels the wool ball in your head and creates a sequential line of ideas that can ultimately form the basis for a wool ball in the minds of your audience.