Some young forwards translate directly to The NHL, others there is a little growing pains because they relied too much on their natural talent in Jrs. Hall is one of the most talented Jr kids I have ever seen. He was physically ready for The NHL, just a monster. He would drive through kids... you can't do that in The NHL. There is a learning curve for him this year, but once he learns correct positioning, he'll be a force.
This reminds me a lot of when Joe Thornton got to the NHL. He was so much bigger and stronger then everyone else in Jrs he just dominated his piers. Over time, he learned the game and he's been a top-5 forward since 2003. Hall will learn the game, and the best place to learn it is in The NHL.