Ultimately this was a tossup for me between Staubitz and McGrattan. Kassian did not really have much of an impact with Vancouver with only one fight (although I am angry Buffalo traded him away). Barch had some activity but his acquisition wasn't exactly necessary considering Florida plays in arguably the softest division in the NHL.
McGrattan did not play much, but he made an impact when he was in the lineup and is my choice for fighter of the year. That being said, Staubitz had more of an impact with Montreal. The only source of toughness Montreal had was Travis Moen
(who only had 3 fights this year) and Ryan White
who demonstrated that he has no fighting skill. Bringing in Staubitz provided the Habs with a physical presence they desperately needed. Staubitz established himself taking on all of the tough guys in Montreal's division (Brown, Neil, Konopka, McCormick). I believe Staubitz had more of an impact than McGrattan so he gets my vote.