Here's one thing I'm happy about: no matter what side you're on with this issue, it appears that everyone thinks that the NFL should mandate helmets that significantly reduce the chance of sustaining concussions.
The Collie hit was clean. I'm not saying that helmet-to-helmet shots aren't going to happen. The NFL has ruled on some hits, like Collie's, that it was inadvertent. But when you launch with your helmet like James Harrison does or like Nick Collins did at Roy Williams, it's illegal and you're going to get fined. It's ALWAYS been illegal. Nothing NEW has been added to the rule book. They just made the punishment harsher and told the refs to enforce the rule more.
The helmet was made as a form of protection, not to be used as a weapon. At some point, players started using bad form and starting breaking a rule that has always existed in regards to the use of the helmet as a weapon. When a defensive player launches himself toward someone, leading with his helmet, it's not a "solid play," it's illegal and always has been.