High hits, targeting the head, extreme boarding, etc. See also: Torres hit on Hossa. At least that's another significant factor.
The problem as I see it is that fighting isn't that significant of contributer anymore. I don't think there's any player within the leage that fights nearly as much as the enforces of yore did but we're still seeing CTE. What you're seeing is a lot of dirty hits--Bertuzzi, Cooke, Torres, Carcillo, etc. and they all get relative slaps on the wrist for it.
Banning fighting won't diminish that aspect. Fighting is already illegal and making it more illegal is not going to deter fuckwads like Orpik. More fighting is likley not the answer (even though it peggs those with healthy reptilian brains with the thought of imagining Tony Twist in his Roid-rage days just completely ragdolling that eunuch), but slaps on the wrist like the DoPS hands out nowadays definitly aren't, either.
The problem, as I see it, is that there's too much focus on fighting which is pretty low in the league and even guys like Bollig aren't doing it night-in/night out like the enforcer days, and not enough focus on getting guys like Orpik, Cooke, Torres, Carcillo, et. al out of the league.
I honestly think that it's going to take a superstar--as in an NHL cash cow getting completely railroaded and their career ended by a blatant cheapshot that's goign to solve that problem since sports leage are always reactionary, not preemptive.