Boston went to game seven and their line up is far from big. Sure they have Chara & Carlo on the back hand, but they also have Krug & Grzelcyk who are undersized. Their forward group is pretty small too. They have only 3 forwards 6'2'' and over in Kuraly, Coyle and Backes. Backes didn't even play in the last games of the finals. You need talent and speed more than anything to win. Penguins are another great example of that.
The smaller Boston team got beat by the bigger St.Louis team, thank-you for proving my point. Since we are giving examples, St. Louis, Washington, Boston, LA, Chicago, and all you can come up with is Pittsburgh?