If you look at the rule changes the previous safety crisis brought on, the game became fundamentally different so I don’t think that’s actually a show stopper.

I actually worry much more about line play than most given the evidence that suggests constant low level head collisions are as dangerous as limited high impact hits for things like cte.

You could imagine mandating standing positions at the line, a wider scrimmage line and mandatory shotgun snaps as rule changes that would limit the constant head collisions linemen take. Just as a for instance.

For a dramatic change you could imagine weight limits like in sprint football.