Well just to be clear, I'm not Bruins Stats, but I believe "they scored a goal" meant Malkin and Kessel scored, albeit on the PP, when they were away from Krejci, DeBrusk, and Heinen.
I would be fine with the Bruins trading Heinen, but it has to be for the right deal. I don't see Coyle as a clear cut upgrade over Heinen, given where both are in their careers, to the point that the Bruins would have to add to acquire him. Donato seems to be figuring things out down in Providence. Who knows, maybe he'll get the call sooner rather than later and fit nicely with DeBrusk and Krejci? If anything, I think the Bruins should be looking for an internal solution to the 2nd line before going out of their way and trading for a top 6 forward. Then spend assets to upgrade the 3rd line which should be cheaper. Right now, I would like to see Heinen, DeBrusk, and Krejci stay as a line.
It also seems like the Bruins would be trading for Coyle so he can play center which I don't think would be the best way to utilize him if the Bruins did acquire him.