Problem for Frost is because he doesn't play a dynamic speed game, he needs to get bigger, that controlled entry and hold the puck stuff means you're gonna draw traffic, and in the NHL the traffic arrives faster and with more attitude. If he had more of a speed game, defenders would back off a bit.
Farabee is going to have a similar issue because of his style of play, while he's strong for his size, hard to play in front of the net and go into corners at 168 lbs in a league where the average defenseman is 6'2 205. But you can see with Cates that it doesn't take that long at that age. He was listed at 6'1 165 a year ago, but looked a lot bigger than that.
Ratcliffe has the same problem as Sanheim, when you're taller, you need more weight to anchor b/c your center of gravity is higher, tall, lean guys will struggle with smaller players with leverage until they fill out. But he's a smooth skater, if he gets more explosive in his stride he'll be a handful down the road. You can see that with Myers, who has filled out and looks like Godzilla on skates out there. A big guy who can skate (which is why everyone slobbers over Morin's potential) just puts so much pressure on opponents in what's becoming a "little man's game" with their size and reach.