Meh. I love love love Burns, in fact he'd be right up there with Subban when it comes to my favourite players, but defensively I don't think he's really even close to Subban. Unfortunately PK will always be undersold in that facet because of his play style, just like Karlsson (although Karlsson isn't really great defensively, he is at least good defensively).
Doughty I can give it to though, he does outdo Subban defensively. In any case, all the mentioned defenseman deserve to be there ahead of Muzzin, and even Shea Weber for that matter. As do Mark Giordano and TJ Brodie (who is vastly, vastly underrated). To get into how I feel about Weber now, I love the guy but he only gets all the praise he does because of his physicality, which is a very overrated way to look at a defender. Going by facts, he is outshone by a lot of other defenseman.