I think it's worth noting that he's really playing a pretty conservative game at the moment because he's a rookie. I expect we'll see more speed and risk from him as he gets comfortable.
His skating is so good though. One thing that always gets me is that his turns to the left (his weak side) are just as tight as to the right. Most players, even at this level, have a side they are more comfortable turning to and you'll notice forecheckers anticipate the turn to the strong side. Dahlin turns to the weak side and it lets him escape pressure. A very nice skill to have as a defenseman.