I feel that hockey "fights" add a certain element to the sport. Allowing players to air their frustrations in quasi-legal means and without dirty hits.
Also fight have always been present in hockey, forcing me to bring up the historical aspect. Without the fights, many people would feel that the childhood sport they grew up to love had changed dramatically.
Minor leagues present excellent play with few fights, could the NHL do the same? I don't know, but it would be a facinating thing to i,implement.