From
TrekMovie:
This episode establishes the Gorn as a continuing big bad for the season, or maybe the series. So the question is: why the Gorn who have some tricky canon issues instead of using the opportunity to create your own whole new villain species?
Akiva Goldsman: Because for me, storytelling beats canon. And that may not be popular, but it’s the truth. So when they can go hand-in-hand, great. But when I was writing the pilot, I was looking for something that was just monstrous, that was Cthulhu-like. Something that was unthinking. Our shows are empathy generators and I wanted to have an element which was in relief of that. I wanted something that you couldn’t identify with, something that was utterly alien, something that was all appetite and instinct in ways that we couldn’t quite understand. And I also wanted to signal place and time in a way that personally I found interesting. So you should definitely blame me for this one.
ALSO...
With Inverse, Goldsman was even clearer on how they are not planning on resolving the differences between how the Gorn were depicted in [TOS] “Arena.”:
Goldsman: You will never see the Gorn like that. This is the Gorn as we perceive them… This is our version of the Gorn. It’s an interpretation. In the same way, the transporter room on the Enterprise is never gonna look like the transporter room looked in TOS, right? It’s our interpretation of it.
The SNW version of the Gorn totally replaces and undercuts what happens in TOS. Goldsman's take totally undermines the theme of “Arena.”
That episode was written by Gene Coon, and it shares a similar theme with “The Devil in the Dark,” which Coon also wrote. Part of the twist of “Arena” is realizing the whole mess is a misunderstanding. The Gorn aren’t “unthinking.” They are not monsters, savages, animals or facehuggers on LV-426. They’re people defending their home. Just like the Horta, maybe before she started dissolving miners the Gorn could have tried communicating with the colonists. But the entire episode is about a future humanity being able to have empathy for something alien and recognizing that maybe the entire situation is a giant mistake.