Late to the party (and not really on topic), but I gotta call this out: unless you're talking Gobert's or Draymond's defense, this a very dubious claim. Melo on offense is not in the same universe as LeBron, Durant, Harden, Curry, Kawhi, or even guys like IT, Lillard, and Irving. He's not near any of them as a scorer (i.e. volume + efficiency) and not near any of them as a passer except possibly Kawhi. Dude hasn't cracked .535 true shooting % in any of the last three seasons, while Curry and KD have both cracked .650, at significantly higher volume.
He's a lot closer to moderately inefficient ball-stoppers like DeRozan, Wiggins and Harrison Barnes on offense than he is to LeBron or KD. Give him LeBron or KD's above-average-ish D, and I still wouldn't consider him a top 20 player.