Kucherov is the second best player in NHL of the modern era. He is playing without Draisaitl(Stamkos wasnt on the level with Draisaitl and now isnt playing for tb at all) and he is the only one who can win art ross against McDavid without McDavid. And should win harts because he is really much more important. He is second best player in pts per game after McDavid after McDavids time starts in NHL(McDavid 1.51 pts\game, Kucherov 1.36, MacKinnon and Draisaitl 1.26). And he is very rare player who achieved two consecutive 30+ play offs(Wayne Gretzky, Mario Lemieux, Nikita Kucherov) and 100 assists in one season(Gretzky, Kucherov, McDavid, Orr, Lemieux).
There are no "Why some would", objective reality he isnt in "that MacK / Drai / possibly even Matthews pantheon''. He is objectively above. As McDavid who is in his own tier.
Lets hope Jack will be some kind of 0.8+ of Kucherov and we will be very happy.