Okay guys, lets clear this up real fast.
While this past season may be an outlier; using his averages (including his rookie campaign and a terrible final year in Arizona) he is still a 60 point, 20 goal player. While those numbers are "just okay", he also has a ton of intangibles (compete level, physicality etc) --- there is a ton of reason to think that not only is this past season not an outlier, but actually an indicator of bigger and better things to come.
This was Domi's first season in the NHL player center. He played between combinations of Drouin, Lehkonen, Shaw and Tatar ... Shaw/Lehkonen are 30-40 point players, Tatar was an overperforming 45-50 point player, and Drouin is an under-performing 70ish point player. Domi had almost 20 points on Drouin, who is the only player comparable in terms of actual raw talent.
Domi also spent a lot of his time on the 1st line; meaning he was playing against top talents down the middle. In a world where Domi is a 1B center OR Domi has a legitimate 70+ point player on his wing, he can easily continue his production if not improve on it.
For his S%age (13.8%) it is only higher than his average because of those two abysmal years in Arizona (8.3/6.0) --- in his rookie campaign, he recorded 11.5, which isn't far off from the 13.8 he had this year. He had positive Corsi, positive Fenwick, and an acceptable FO% --- absolutely ridiculous to claim that Domi is going to regress by a factor > than 7-10 points.
There are very very few players in the NHL I would trade Domi for given his intangibles. Similarly to Gallagher, I would want a massive over-payment to consider moving on from him, especially if he can do what he did this year, again next year (which I believe is a given).
Given position, I'd say he's a little less valuable than a Larkin or Kuznetsov, but a little more valuable than players like RyJo, Sam Reinhart, RNH or Boeser.