Habs fan here. I saw what you say about his speed the last year he was an Habs player. And he was younger and faster. I would say to you he was so freaking fast in his two first years in nhl. It was wow spectaculor every shift. And I'm not talking about his big hits among the boards. Then he got more muscles, more weight and got slower. Just a little bit but still, he was fast enough to be an elite nhl player. Overall, he was more efficient scoring goals and being offensive than stricky a defenceman in his own zone. At the time, we were able to compare with another top defenseman Erik Karlsson from the Ottawa Senators. Karlsson was much faster than PK I can say. And still is today. But PK is a bigger guy and tougher.
Because Mtl Canadians was a bad team with weak offensive players, PK was taking too many chances and tryed to carry the offense all by himself. Example, he dekes one player, then another one and then he was stopped in the offensive zone and create a turnover. His teamates didn't know how to deal with that. The Mtl Canadiens board was very divised about him. There was his haters and his diehard fans. I watched some Nashville games after his trade and I saw a very different PK, playing a team game, not taking too many chances, a perfect PK. He would never have been traded if he had play a team game like in Nashville. I can say many hockey journalists said he has been largely overpaid with his 9 M, it's one of our gm's mistake, like the overpaid goalie Price with 10,5 M. Seabrook was paid 5 M at that time.
Now we have Weber, a beloved player or an hated player, depending on mtl boards members, we are very "bipolar" in Montreal, lol. But that's another story.