I think if you combine modern player speed/size with 70s era rules, concussions aren't going to be the primary issue in the player safety discussion anymore. That being said, all the rules related to illegal hits and so forth have made the game infinitely more complicated to officiate, and I think that, more so than any major decline in the quality of officials, is the problem with officiating.
It's completely counter-intuitive and will never happen, but I personally think they'd make the game "safer" if they used less safety equipment. Defensive players risk almost nothing in blowing up "defenseless" players, the physics is entirely with them. They might make different decisions if they had to worry about smashing up their face or something of the like.