People keep referring to the "Penguins Model" of highly skilled offense coupled with low-cost (perceived as low-skill) defense. I don't think that's what Toronto is using as a template. It's well known that Shannahan is trying to build a puck-possession focused team like his Detroit days. While it's not possible to get the Larionovs, Kozlovs and Konstantinovs to make it happen as well as those teams, I believe that's the style Shanny is envisioning. That's why it was important for him to get Babcock to implement that style. Presumably, that is the vision that Dubas is implementing with his roster. This will result in players that are creative, skilled, and not necessarily known for their bruising ways. This includes the defense, hence the selections of guys like Sandin in the draft when a more defensive D-man is what everyone assumes they need.
Perhaps it is a shortcoming of NHL fans to be caught up in seeing what was successful, and then assuming that if the parts aren't exactly the same, it won't work. (eg. "Crosby/Malkin is way better than Matthews/Tavares," so Leafs can't win.)
There's no fool-proof formula for constructing a winning team. Is every Cup Winner a perfectly constructed team with no faults? Are they all mirror images of past winners? Of course not. It's a question of being able to overcome team weaknesses with strengths; the same for every team. Whether it happens or not is why we watch the games.