While under normal circumstances I would agree with your thoughts about the Boston forwards, you're comparing a goal-less Jagr (with 7 assists in 16 games) and Tyler Seguin (1 goal, 4 points, -1 rating) with Shaw (4g, 3a, +6), and Bickell (8, 3, +5) ... not so much Saad, but the point is still relevant.
Defensively, for me, it's not even close. Even when the Bruins are healthy - which they aren't - the Hawks have Keith, Seabrook, Oduya, Hjalmarsson, Roszival, and Nick Leddy. They can all skate, they can all chip in offensively, and they can all play defense. In my opinion, Chicago has the best all-around defense in the league.
The Blackhawks have been the best team in the league all year. They have faced better competition than the Bruins (except in this round), and have fared better overall. I'll take the Hawks in 6 ... that is with the assumption that they finish off the Kings.