If the NHL wants to get serious about concussions, they need to get serious about repeat offenders like Matt Cooke, who has repeatedly displayed a complete disregard for the rules, and for the health of his opponents. This isn't "reputation," this is a repeat offender. And suspending repeat offenders for 4, 6, even 8 games is insufficient.
The NHL needs to implement an escalating punishment scale for these kinds of hits. Sort of like what MLB does with steroids, or the NFL does with their "substance abuse policy." First offense, 2-4 games. Second offense 5-10 games. Third offense 10-20 games. Fourth offense is 20 to 40. Fifth offense is an 80 game suspension. Sixth offense: permanent banishment.
Now this would only be for blatantly intentional head shots like this. It wouldn't get rid of concussions in the NHL, because it's a fast paced, hard hitting game. But it might make the Matt Cookes of the world think twice before charging and elbowing a defenseless player.
And it might make Mario Lemieux think twice when assembling his team.