I know many here will disagree with me, but I think the fact that average sports fans won't or don't watch the NHL is because the league refuses to shake its "Slapshot" image, which puts it at just above the level of pro wrestling in the public's view.
I have friends and relatives who will watch the Sioux whenever they can, but absolutely refuse to watch the NHL because they equate pro hockey with goonery and fighting.
And why shouldn't they? What hockey moments are guaranteed to make the sports highlights of practically every broadcast around the country? Of course, it's the big fights or instances of players acting like street thugs. As long as hockey fans cling to the notion that "fighting is part of the game," our sport will always play second fiddle to football, basketball and baseball.
As others here have noted, it wouldn't hurt to open up the game by eliminating the two-line pass rule and strictly enforcing the rules on obstruction and interference. If I were in charge of the NHL, I'd also made full cages or face shields mandatory (as they are in college) and switch to Olympic-size ice.
Rip away.