I don’t think you have to disagree with the fact that Fox is a great defenseman to simultaneously assert that he has limitations that other D who are very similar, in terms of quantifiable metrics, don’t have. I also think anyone who takes the stance that there’s no such thing as intangibles - or things analytics can’t account for - in hockey, is out to lunch. Therefore, I don’t feel the need to justify my feelings on Fox.
He’s a great defenseman but his skating in particular is a limitation which, to me, is significant in the game of hockey. If I am building a team, I want a thoroughbred as my #1D, and even if that thoroughbred is only in the top 10 range instead of the top 3, I would likely choose them 10/10 times over a top 3 D with weak skating. To me, your top D and best puck mover needs to be a dynamic skater.
For me, the intangible effect of having an effortless, superlative skater as your top D is one of the most significant in the game. That’s just me. Fox will always be lacking there and while his game doesn’t rely on athleticism to be effective, there is still a point at which skating becomes an issue for any player. The better of a skater you are, the more steps you can afford to lose to age and injury. Fox maintaining his skating at its current level for as long as possible is essential. He has far less runway than many, and certainly less than the vast majority of top D in this league.
Is Mitch Marner a great, super talented forward? Is Stutzle? Hughes? Bratt? Reinhart? Keller? Hintz? Robertson? Nylander?
Do you like them all equally? Do you have preferences? I prefer Stutzle and Hintz, who I l’d wager are probably the two fastest, but also have two of the nastiest wrist shots and both who play with a bit more physicality than all of the others. Stutz in particular is not just fast but an electric skater, while Hintz is the most physical and also the most explosive and powerful skater. We all have ideas on the ideal types of players to win with. There’s some people who, while acknowledging Fox is a great defender, feel that the skating leaves something to be desired and have concerns about how Fox is going age. Maintaining peak physical shape does not seem to be a Mackinnon-esque priority for him.