It’s very simple - generational is a player that will probably only be seen a handful of times in that generation, which to me is about the approximate career length of a forward, so let’s say around 15 years (ie when the “passing of the torch” happens from one set of generational
Players to the next). The only ones in this “generation” are Crosby, Ovechkin, and McDavid. End of story.
I freaking love Kakko but he isn’t generational. Neither is Pettersson. Neither is Hughes. Probably not even Dahlin, until he proves he has another few levels to his game.