In response to asmaha's comment:
Even before all this, it's tough to see exactly what direction the Bs blue line is going and what "hole" needs to be filled in their eyes. CJ is moving pieces around, and even then he's often had one set of pairings during the regular season then mixes it up come playoffs. Media seems to think it's a fait accompli that Chara-Boychuck become the shutdown pair, but that bothers me in the short term. Reliability/experience is thin once you get past Chara and Boychuck, and putting them out there together now in the regular season is just begging the other team to exploit the times they're off the ice.
So why not move McQuaid (or Bartkowski) up with Chara and have him play a simple stay-at-home game? Boychuck-Hamilton then becomes a steady 2nd pairing, and there's nothing wrong with Krug/McQuaid/Bart as the 3rd. I'd just like to see them spread out the experience a bit here in the regular season, then evaluate if the need is for someone to pair up with Chara, or Boychuck gets the nod and the search is for someone to join Hamilton in the 2nd.
I just can't see the Bruins employing defence pair that are same handed. They haven't really done so in the Chara years. Seidenberg being the only exception and he's not an option anymore. I'm not sure he would have been there this year with the development of Hamilton and no Ference to balance the 2nd pair. I do not really like Hamilton/Boychuk as a 2nd pair and the same shooting is only part of the reason. I think your closing sentence nails it. Kris Russell is an excellent suggestion I wonder if some would find him on the small side