I was thinking about this, too, and I'd at least like to see it tried at some point down the stretch. The two main issues with this: 1) I don't think Ferraro is particularly good at moving bodies at the front of the net, and Merkley certainly isn't, so they could get hurt there, and 2) For all the challenges Ferraro has faced paired with Burns, it's always hard to find someone to work in that pairing, and I don't know that Vlasic or Simek can do it at any reasonable level.
But if the plan going into next season is to continue on trying to compete, the best approach might be to try to distribute the team's top defensemen across three pairings and the special teams units. Clearly the plan is to not overwork Karlsson, which makes sense, but Burns and Ferraro also shouldn't be getting ridden into the ground. If we accept Middleton as a solid partner for Karlsson, then the trick would be finding someone to work with Burns.
If the top guys are playing fewer minutes but better minutes, it would certainly be a net benefit to the team. But I don't know that Boughner could bring himself to do something like this.