It's a label meant to minimize him and allow your brain to more easily wrap around the concept of his replaceability and tradability. (I wondered where I've heard that Ozolinsh label before. That's a JXC-ism. He's used it countless times. Ozolinsh was also a top offensive d-man and Cup winner. And Ghost can be and has showed better.)
Elite puck skills, shooting, deception, entry/exit ability, PP QBing, an even larger sample size of him playing with Provorov on one of the best pairs in the league......that's not niche in my book. That's called positive on-ice value. The only thing that matters. Even if he's a "niche" player, it's a "niche" we can't replace at a cost we can't match. No one calls an elite defensive defenseman a niche player, or even an elite offensive winger. It's purposefully negative in connotation and yet another tacit admission you want him gone desperately for reasons no more complex than bias, boredom, and short-sightedness. You'll deny it; we won't buy it. Round and round we go.