I'll admit off the top that I'm biased. I'll try to keep this as objective as possible.
By suspending Aaron Rome, the NHL seems to have said:
"Enough is enough. If you hit a player in a way that is worthy of even a two-minute penalty, and that player is injured, you're getting suspended."
It's a way to make players responsible for their actions. It's a way to tell fans that they're responding when something goes wrong.
Something has gone wrong. Mason Raymond is out for 3-4 months with a vertebrae injury resulting from a hit by Johnny Boychuk.
Was the hit legal? No way. Boychuk tied up Raymond as the two were going for the puck. That's legal. Maybe you could argue there was some hooking or holding or interference...but I'm not too concerned. After all, it wasn't that action that led to any injury.
Instead, it's the subsequent action where Boychuk guides a bent-over Raymond, ass-end first, into the end boards. This occurs long after the puck has gone by and over 10 feet from where the play occurred. It's easily over the '0.5 seconds' guideline the league used for the Rome/Horton hit. A hit made late, resulting in an injury, should result in a suspension.
What's more, Boychuk doesn't just ride Raymond into the boards. He gives him a solid shot to the back as they go in. Raymond is half Boychuk's size. Hitting a player into the boards in a dangerous manner, particularly when the player is in a vulnerable position, is called Boarding. Boarding is a penalty. When a player is badly injured in a boarding incident, the appropriate penalty is a 5-minute major and a game misconduct. A 4-game suspension, by the NHL's recent logic, should follow.