1). He is a skilled speaker, with help.
2). He does not pause to "let us catch up", and rarely do I find myself needing to catch up to him.
3). He does not pause to "let his words resonate", but that would be a good reason if it were true.
4). He does not pause to "let us rest", and I've never felt mentally exhausted trying to grasp his words.
5). His pauses do not give an impression of composure, though I could see him pulling off thoughtfulness. Pausing like he does every speech shows me the opposite of composure. I learned that from my cultural anthropology teacher.
Those aren't rose-colored glasses. He has Obama painted on the inside of the lenses.