It is so difficult to rate defensemen over the decades: the game has changed so much, the ideal of the perfect defensemen has evolved so much.
When I was a kid in the last years of the Original Six, the concept of an offensive defensemen did not really exist. You did have some guys like Pierre Pilote with Chicago and JC Tremblay with Montreal who piled up assists on the power play but the ideal was defense first/strong in front of the net, never carry the puck into the offensive zone. Guys like Tim Horton and Doug Harvey.
Along came Bobby Orr and completely changed the game. Every team then went out looking for guys who could rush the puck, shot, but still play strong D: Dennis Potvin, Brad Park. BTW, when Park first came up, I vividly recall his first game, we in the blue seats named him, "the baby faced killer."
Then, in the free-wheeling 80s, we had guys like Paul Coffey: offense first, defense second.
Then we transitioned to a more balanced concept: guys who could still rush the puck but were also fine defensively: Leetch fits right in here. Lidstrom, for sure. Ray Bourque, probably the most perfect Dman I have ever seen, a guy who rarely made mistakes.
Now, we are in the era of the ideal being a guy who can, first and foremost, carry the puck out of the zone, minimizing time spent in the defensive zone.
Brad Park was the perfect D for his era. Leetch was the perfect D for his era. Adam Fox might be developing into the perfect D man for his era.
It is so difficult comparing eras, The game is just so much faster now. I watch tapes of games from the 60s and 70s, even the 80s, and I am always struck with how slow the game was. It didn't seem so at the time: it seemed fast. But today's game? As a fan since the late 1950s, I am continually amazed at the speed of today's game. It is often breathtaking.
Another tidbit: there is most definitely a bias against NY players, a belief that NY hype exaggerates a players ability. We see it on the main boards where people say Henrik was overrated. Heck, if anything, I think he was underrated.
Anyone who thinks Leetch was overrated simply is letting their bias overwhelm reality.