I don't think it's fair to compare Detroit vs Chicago when talking about playoff tests anyway. Any rivalry matchup like that levels the playing field based purely on the hatred. On paper Chicago should be killing Detroit, but the bad blood neutralizes any advantages Chicago would otherwise have.
As for the Penguins, the Islanders definitely challenged them with their speed. New York was arguably the fastest team in the playoffs and that exposed the Penguins defense. It's not as though they don't have some high-end talent. As for Ottawa, they were the East's top-rated defense with a goalie that posted pretty incredible numbers this season. It's a little weird to hold it against Pittsburgh instead of giving them any credit for making it a short series.
I understand the point that New York and Ottawa aren't particularly experienced teams, and that Boston has more veteran players than either of them, but it's hard not to have Pittsburgh as the favorite to come out of the East. The Bruins are looking better than they did in their series against Toronto and compared to how they played the second half of the season in general but I'm still not sure about them; they have not seemed themselves since February or early March.