Flaws are a good thing? Ok, I’m done here.
It's stated a tad flippantly, but it makes total sense.
Say you've got a kid 6'2" 190lb great skater, hard worker, very physically fit and he's putting up 30G 40A 70P
Now you've got another kid 6'2" 170lb eh skater, a bit lax on defense, pretty soft physically and he's putting up 30G 40A 70P
Who can you work with and improve more? Is there a higher chance of complete failure? Absolutely. But if there are obvious factors that a coaching staff can work on to improve a player, the gains will be much bigger than a guy that's already playing a pro game with a pro body.
It shouldn't be a matter of who is the best 17-18 year-old playing against juniors. It's a matter of who has the most runway/best odds to become a better player in his 20s against pros. Some times you might want to pick a safer player. But we have safe coming out of the woodwork. Danielson has a much smaller chance of becoming a 1st line NHLer than say Matthew Wood, even though he has a much higher chance of becoming an NHLer at all.