I don't and never have believed that it should be a principal object of the game to hit your opponent as hard as you possibly can at all times. That because a guy has his head down, that somehow he deserves to be launched into the cheap seats. I think this mentality shows a total lack of respect for your opponent.
The point of bodychecking should be to remove the player from the puck. That's all. That's why it's illegal to bodycheck players who don't have the puck. There is nothing wrong with a good clean hit and I hope hitting never leaves the game, but if your intention in throwing the hit was to hit the guy as hard as humanly possible, then you're missing the point.
Bobby Clarke (who played in what the oldtimers will call the 'good old days') said about a year ago that the cause of the head injury problem in the game today is that players today treat their bodies like a heat-seeking missile. He said in his day, players threw hits to knock the other guy off the puck, that's all. Today they throw hits to try and knock the other guy's block off and the puck is an afterthought.
Maybe it's because in Clarke's day they didn't wear helmets and the equipment was flimsy by today's standards, so everyone was more aware of the possibility of serious head injury and thus they respected their opponents more. But that level of respect is long gone today, replaced with a level of recklessness. And it shouldn't surprise us that with recklessness comes more injuries.