Three things jump out to me about Dahlin.
Skating - he’s one of the best skating D in the entire league already. Other guys have faster breakaway speed, but he’s incredibly efficient and so good on his edges. His skating is so elusive that he can just make guys mis read what he’s doing all the time.
Skill/Hands - His hands are superb, he can stick handle in a phone booth and again is one of the best D already in terms of puck skills. He’s so creative with what he does out there, and never ever has to look down at the puck.
Hockey IQ - Reads the game so much differently then most players, he’s not Connor McDavid where he’s processing the play a million miles per second. He’s more of a guy so can hang on the puck and just wait guys out and use patience to his advantage.
The biggest weakness right now for him is that he shoots the puck like an 18 year old, but no question in my mind this is a franchise Dman and one of the best U20 D to ever play in the league.