It may not have been Fistric's intent to try to decapitate Niederreiter, but he clearly leaves his feet to deliver the check, which has always has been a penalizable offense for charging. He also made direct impact with the head, which in the current NHL is a big no-no.
I had said in the thread about the hearing that prior to this season I don't think this should have been a suspension. But given that this year they've already suspended guys for cleaner hits in my opinion (Clarke MacArthur is always my stock example), a "headshot" that results from a check that has always been illegal (a charge) should be suspendable by the current standards. They've also been factoring injury on the play (Niederreiter was concussed) and past disciplinary history into decisions. I was thinking 2 games would be a fair number, but I guess due to the injury and Fistric having a previous, albeit brief, record of subsequent discipline, it earned him an extra game off.
Here's the Shanahan video for anyone interested: