I read the article. I think when people are talking about an improvement in Ovie's defense they're talking about (1) a significant one vs. last year, which seems like it must be true, and (2) a slight improvement in general over the other years.
It's all hard to reduce to numbers for a number of reasons, but one of those reasons is that there is an element of overwhelming offense itself being good defense, I think. Under Boudreau there was some truly overwhelming offense happening at least for the first half of his time here.
And maybe Ovechkin's improved passing this year might be getting conflated with a commitment to team defense a little bit and maybe the article's not that far off when it says his defense isn't really all that much better than his previous best defensive years. But no one's gonna tell me he isn't more of an overall team player this year, while still potting 50, and no one's gonna tell me that this hasn't been the best year overall of his career.
Not saying the article is trying to tell me any of this--just saying that, y'know, we can quibble about whether his defense really improved or whatever, but it kinda doesn't matter to me. He's a better overall player right now, no one's ever gonna mistake him for Datsyuk or whatever other famous two-way guy you want to bring up, and I'd still rather have Ovechkin in any given season than any of those guys, especially the Ovechkin of this season.