One of the easiest ways for a prospect to drop to be undervalued in the draft is to be small. This is especially true for defensemen, who are required to be much more physical than, say, a winger. But the NHL is slowly moving away from that. There were 59 defensemen to play in the NHL this past season who were shorter than 6’0”. Ten years ago, there was 42. Ten years before that, there was only 28.
The game of hockey in the NHL is moving more towards speed and possession, including dynamic skill at every position on the ice.