Comments like that literally get me mad. It's like someone trying to prop up some mediocre basketball player and comparing them to Magic Johnson or Michael Jordan.
No, Knack is not a love letter to old school platforming. It's a piss poor attempt at trying to recreate an old school platformer, and I think it fails pretty hard at doing that.
The character design alone is nowhere near as charming as Crash Bandicoot, or Mario, or Sly Cooper, or Ratchet & Clank. That voice when he's big? LOL, NO
The gameplay is incredibly basic, and the enemies, oh don't even get me started. This game made me cringe the first time I saw it, and I wanted to like it, because I like these style of game, but no, in the end I think people are purely giving it praise while wearing launch goggles.