There are unusual things about Trump's communication: extreme informality, seemingly not running things past advisors or editors (for both speech and writing), and probably making things a lot more personal than other presidents have done (talking more about himself; talking more about his experiences, opinions, and emotions; talking more about individual friends and enemies). Maybe also a far greater willingness to make digressions, whether personal or not.
Still, I think the prior commenter is right that we can be surprised by how disfluent almost everyone's extemporaneous speech appears when precisely transcribed. This is often hidden because published interviews or speeches in the press are usually extensively edited, so you won't see something like
"And I, um, I said, well you know, I said that we-- we're going to fix this pro--problem, uh, this problem that's been affecting a lot, a lot of people."
Instead, you'll see something like
"And I said that we're going to fix this problem that's been affecting a lot of people."
There was a big controversy about Dan Quayle as vice president and about George W. Bush as president because they both seemed to make a lot of speech errors and misstatements. I think I remember some linguists complaining that the oddities of both Quayle's and Bush's were probably being exaggerated merely because people were paying such close attention but were unaccustomed to seeing carefully transcribed speech. And I think the same is true for Trump's speech, even though he is also flouting various communication norms in both his writing and his speech, sometimes consciously.
Earlier presidents also had more patience for delivering prepared written speeches, from paper or from a teleprompter. For many of their speeches, they were extemporizing less, and when they did extemporize, they were comparatively better at keeping on-topic.
There are people who take these transcripts and re-enact what he's actually saying, but in their voice.
Doing that makes it immediately obvious that he's a rambling moron.