Him and Mbappe are the fastest well known players right now. A good manager would have known how to use his pace effectively by creating space for him on the wing to burst into, creating 1v1 situations. Dembele under EV however is often forced to get the ball with his back to goal when also being pressed, which frequently results in losses of the ball. There were also a couple of instances when he accelerated, put in a low cross but no one was in the box. A familiar scene from the last season as well. De Bruyne for instance does not even look when crossing, he just puts it into the dangerous area and knows that someone will be there because Man City are drilled to always have a player on the far post. Dembele often does the same, but his crosses are intercepted because we are not quick enough to attack the space. Look at Dembele's assists for Dortmund, about 50% of them came from low crosses to the far post to Aubameyang.