I think there's a big difference between "psychopaths" and rough, aggressive, tough players.
Okay, the Messiers and Stevens crossed the line once in a while with the elbows and late-hits, but otherwise I never had a problem with those kinds of players. They were 95% clean, high-skilled players who played with an edge. (They also didn't run away from physical encounters.)
When I was a kid in the 80s/90s, I did not enjoy the rough stuff much -- the staged fights, and the goonery, I thought was ridiculous. The League did the right (and inevitable) thing in getting rid of that. I'm talking about the bench-clearing brawls, late hits after the whistle, scrums every single time after the whistle delaying the game, goons who only play 4 minutes a game with no intention of playing hockey, players starting fights with 30 seconds left in 7 - 1 games, players injuring other players seemingly by coach's orders (Bobby Clarke, Kypreos) etc. Those kind of playground antics I always found unsportsmanlike and stupid, and I don't miss it.
But I do miss more tough stuff. I remember a great moment in the 1990 Cup Finals when Craig MacTavish and a frustrated Cam Neely, for example, were jostling for position in front of the Oilers' net, and they spontaneously dropped the gloves and had a brief 'rasslin' match. There was nothing dirty, no injury, no sticks, no pre-planned fighting, no psychopathology. Just two good players boiling over and not wanting to give an inch. Or, to use a more famous and full-on example, the epic Iginla vs. Lecavalier fight in the 2004 Finals. That was awesome!
I just don't see that stuff happening anymore, or at least very rarely.
EDIT: So, something's lost but something's gained. Still, I can envision where, in 20 years, the hockey warm-up is going to be like the NBA where all the players on different teams are chatting about their kids and mutually back-slapping each other right before the puck drops for game seven.