I wish in a few cases the NFL would change the rules to make the game a little safer for its players. Some of the rules could be changed without making the game less enjoyable.
For example:
1. Ban all chop blocks. Right now, it's legal between the tackles.
2. Enforce a ban on leading with the helmet when tackling.
3. The college rule is that the snapper has to be given that half-second to position himself before he can be hit. Adopt that rule for the pros.
They could also Look into improving the helmets. A few players, such as the 49ers Steve Wallace, put styrofoam padding over their helmets. It's unclear whether that helped, but some kind of mandatory padding on all helmets might make the game safer. It's worth checking out.
Get rid of astroturf. After a game on grass it would only take a day to recover. The one or two games a year I'd play on turf would rip me up for 3-4 days. I can only imagine how rough it would be in the pros with 250 lb linebackers smashing down on you and you land on a carpet thrown over concrete.
Plus the turf increases concussions and torn ligaments.