I have seen this video more then twice and did not see any NBA level speed or quickness there. I asked specifically for at least one particular play. Could you point it in that video?
He has long stride on his first step which helps him beat slower inferior competition he is playing against. Compare his speed, quickness and explosiveness with Gordon for example, day and night. I see Exum struggling vs NBA speed and defenses, he is just nothing special.
He's got speed. He's blowing by people in the open floor, including the Nike Summit game against decent athletes.