We see this type of player over-drafted every year. This year was Hayton, last year was Rasmussen and Andersson. McLeod was the year before. You could honestly even argue Jost would apply, although I think he earned his draft position with his WJC18 tournament.
I don't understand why teams do this. Centers are not that important that you ignore your scouts evaluation of their abilities. There's a small chance these players turn into a Horvat profile of player, but the fact that their offensive game is so questionable to begin with and they have to be typed as a defensive guy who might have "underrated" offensive upside probably means their offensive upside isn't very high. There's also a small chance Wahlstrom is Bossy or Kotkaniemi is Kopitar. Doesn't mean the best-case scenario should be used as a reason to draft a completely different person. There's no reason for teams to try to force picks into being high-end centers. Either they have top 10 or so ability or not.
The mental contortion that is used to explain away these picks is bizarre. I’ve heard it for over a year from my team and I have no respect for it.
Hayton's scoring isn't great, but it wasn't crippling either. Especially when you know his usage. He got drafted a bit too high, but, finding quality centers outside the top 10 of the draft is a significant challenge. I'd also add, it wouldn't be fair to use those comparrisons for those 2, and then just cap Hayton at Horvat (if you are going to extremes atleast use Bergeron). Look at the NHL.com top 20 Centers (I'm just using that due to it being a recent, and a list that while placement can be argued, is probably close to an accurate unbiased representation of the top 20 centers in the league).
1: McDavid (1st Overall)
2: Crosby (1st Overall)
3: Malkin (2nd Overall)
4: Matthews (1st Overall)
5: MacKinnon (1st Overall)
6: Kopitar (11th Overall)
7: Scheifele (7th Overall)
8: Bergeron (45th Overall)
9: Seguin (2nd Overall)
10: Tavares (1st Overall)
11: Stamkos (1st Overall)
12: Kuznetsov (26th Overall)
13: Barkov (2nd Overall)
14: Backstrom (5th Overall)
15: Eichel (2nd Overall)
16: Barzal (16th Overall)
17: William Karlsson (53rd Overall)
18: Couturier (8th Overall)
19: Getzlaf (19th Overall)
20: Draisaitl (3rd Overall)
Now, that just shows how good centers are almost exclusively found at the top of the draft, in most cases, the very top. 50% of the list was drafted in the top 2, another 10% were taken between 3 and 5, another 10% between 6-10. So, about 70% of the leagues top centers were taken in the top 10, with 50% coming in the top 2 picks. We have 2 picks outside the 1st round. Kuznetsov was a top 10 talent who slipped based on being Russian at the height of the KHL scare and making his willingness to come over unclear. Compare this to any other positional list like D-men or wingers, and the breakdown would not be this extreme. Looking quickly at wingers 30% of the top 20 were taken outside the first round (compared to 10% of Centers) and significantly more were taken outside the top 10 in total (60% to 30%), obviously, the example of Kuznetsov applies to Kucherov and Tarasenko. Looking at defenders, its quite similar. With 35% of the defenders being drafted outside the first round (I will admit, the D list seems to be the biggest mess on first glance, but that doesn't mean it isn't representative). Outside of the top 10 is where 60% of the defenders were drafted.
Now, I think Kotkaniemi and Hayton were probably overdrafted. But, teams that are picking high, and don't think they will likely be picking high again, may be prone to reaching and taking a valid chance. Finding centers outside of the very top of the draft is extremely challenging, its the one position where finding good ones outside of the first round is extremely hard. Given forwards are easier to project, and the value attached to centers, it makes sense to occasionally slightly reach for them if your system is barren of them. I mean, league-wide how many legitimate top 60 centers are there who were taken past the first round? Off the top of my head, I got Stepen, Point, Tyler Johnson, Vincent Trochek, Krejci, and ROR.