He was never actually that good. He was just a battering ram of a defenseman who drove people through the glass and made highlight reels for his hits, so he was held up by a certain variety of fan (and by certain dinosaur Leafs GMs) as the greatest thing ever because the rest of the league is too damn soft, blah blah blah. In reality, he was never a great skater, had the hockey IQ of a cucumber, routinely took himself out of the play to make big hits in a way that cost his team goals. If you wanted highlight reel hits, he was your guy. If you wanted to stop the other team from scoring goals, he really wasn't.
And now he's slowed down and is even worse. You can't bring him in to be physical, because he's too slow to hit people. His positional defensive awareness is that of a peanut, and he can't react in time anyway. He hasn't been a useful player in the NHL for years now, but thanks to that dumbass contract the Leafs gave him, no team has been able to afford to dump him off the ice until the Kings finally bit the bullet.