Business is no place for stream of consciousness babbling, no matter how colorful you might think you're being. You will discover that you can be an effective editor by cutting out everything that isn't absolutely necessary. Knowing where you're going in your conversation by being concise is a big step toward leadership and respect. People appreciate brevity in today's world.
-- Donald Trump (Think Like a Champion)
Generally, I tend to agree with this position, but with a specific exemption - sometimes there is need and value in putting completeness over brevity. Yes, in most cases it's beneficial to refrain from wandering all over the map. On occasion, however, a presentation needs to not only be complete but redundantly complete. Some things are so important that making sure all aspects are covered, and all participants are fully understanding all the angles and options is critical. If that means an extra half hour of "yeah, I got this," I argue that sometimes it's okay.
Now, all that said, I find it ironic that this advice, like much in his short book, Mr. Trump can't seem to heed, himself. Just his twitter feed alone puts the lie to the suggestion that he takes his own advice. And if you tuned in to any of his speeches where he goes off-script, well... enough said.