No, I think his return to form is a function of a couple of things, but certainly Berube's system is one factor. He's played similarly before the 4 Nations. I think what's changed for some is perhaps not unlike what they see having changed for Marner, and that's the same player in a different setting/uniform.
A good reminder of the player he was before the big money, with Keefe, and now under Berube.
Remains to be seen what effect the tournament and its surroundings have on him as it relates to his play and then as important, his commitment to team goals a la Crosby, Marchand...