Everyone on your list quickly established themselves as high scoring players in each respective league in their first year
No, that is how it is being used but a simple check of the stats shows it is being used in a very misleading way.
Sorted by PPG in first AHL season. First 7 players (plus Hunter) in blue have PPG's that are reasonably similar and could be easily impacted by linemates, ice time, and PP usage. None of those 7 players have numbers significantly better than Hunters, and that isn't even factoring his injury.
Second group definitely established themselves very quickly in the AHL, but 4 of them (grey) are at least a year older than Hunter (Deharnais was +2 years). Not to mention Koivu, Filppula, and Deharnais all played at a pro level BEFORE they got the AHL while Hunter is making the jump from CHL/junior.
There are really only 2 players who are comparable to Hunter this year, namely Mark Stone (put up .7 PPG at age 20 out of CHL) and Jiri Hudler (.86 PPG at 19 out of Czech league). And this notion that elite players come in, put up one big season, and breeze onto the NHL is another falsehood, at least using the players in this list. 5 players spent at least 3 full seasons in the AHL while 5 spent at least 2 (Nyquist looks like 3 but his first season at 21 he played only 8 games). Only Filppulla and Koivu left after only a single season in the A.
So no, this list certainly does not show that "Everyone on your list quickly established themselves as high scoring players in each respective league in their first year". Their progression was more or less like Hunter's, albeit maybe a bit 'smoother' due to his surgery and rehab time. Some certainly did establish themselves a bit better however you cannot ignore what being a year or two older or having played pro already does in terms of prepping these kids for the AHL level.
That isn't to say I believe Hunter is necessarily a blue chipper or destined for a top line role in the NHL, as my views on him are more as a useful secondary scorer. But people need to stop using this list as some sort of evidence that his first season must be PPG or else he can never reach the heights of the great Ondrej Palat or David Deharnais. Simply not correct.