if you didn't watch the XFL, you should check out their kickoff rules/formation. The kickoff team stands at the 35, the receiving team is only 5 yards away at the 30. None of them can move until the kick returner catches the kick.
This really seemed to cut down on the collisions which should greatly reduce concussions. Remember the NFL concedes the vast majority of the concussions come on special team plays. The NFL has already said it was looking at changing the kickoff. Wondering if they'll move to adopt the XFL policy.