One reason Flahr talks about adding strength is they are drafting more skilled players who need to fill out rather than big boys like Bunnaman and Twarynski who needed to add skill.
He doesn't talk about strength much with Kaplan, for obvious reasons, or Gauthier.
But guys like McLaughin and Avon were skinny kids when drafted, and if you're not as skilled as Point, yes, you need to add strength b/c you're not going to make your living deking through three defenders. Samson was 6'0 181, hard to play defense at that size unless you have Makar like skills. It's one thing to push around 17 year old kids in the CHL, but 3 years after they're drafted, they're in the AHL playing against men who know all the dirty tricks.
And it's a balance, as he observed with Wisdom, who lost weight, got in better shape, but is struggling now that he can't just bull through people. Nutrition and training are keys to any player development program in both hockey and baseball, where you draft 18 year olds and spend 4-5 years developing them. Even NFL teams obsess over it, and they draft 22-23 year olds.