http://www.youtube.com/watch?v=f_Wxm6hw8MA
I don't see how this hit is in anyway similar to the Depres hit outside of both players ending up with their helmets off. Letang hits a player in open ice clearly on his shoulder and only his shoulder while that player is alone. The helmet flys off at another angle from Letang's impact showing it's clearly "whiplashed" off.
The "follow" through of Neals elbow/forearm into Depres' head is what knocks his helmet off. "Whiplash" would imply that Depres' head was still moving forward while his mid to lower body was hit and thus moving backwards. You can see from the Depres hit that his head is "leading" the motion of his body implying it was the principal point of contact. The helmet also is "impacted" opposite the direction of the hit and falls behind Depres.
I still hate these hits where 1 player is already "engaged" with another. It is just way too difficult to pay attention to both and the puck. I thought the old Kunitz hit on Timmonen was just as bad and should've been suspended IMO.
https://www.youtube.com/watch?v=VSgcACSR9L4