Back to the original topic, one aspect of sci-fi's current trend is "darker and grittier." That, to me, is a delicate line to walk, because Trek was always about optimism about humanity and the ability for human to overcome challenges and move past some of the more petty issues that were a part of the culture at the time (racism, nuclear war, among others).
Optimism needs to be at the core of any new Star Trek series. I've seen lots of interesting pitches, and would love to see them developed. Just not 100% certain they would fit in Trek.
In TOS there are indeed some genuine dark moments even by today's standards.
In "The Enemy Within" the evil Kirk's attempted rape of Janice Rand is pretty dark and intense. And yet there was no graphic violence in the depiction. Today you might push a scene like that just a bit further and filmed right (so to speak) it could still come across quite dark and disturbing.
Another chilling scene even without any violence seen whatsoever was in "And The Children Shall Lead" when Kirk and Spock realize they've just beamed two security men out in to space while in warp flight. Those men died instantly and it's damned chilling just to imagine the final thoughts of those men when they materialized in vacuum.
Matt Decker describing his crew calling for help as the planet wrecker is beginning to slice up the planet and Decker, now alone, is helpless to do anything with his ship a broken hulk. It's all in William Windom's performance and the accompanying music that plays with the viewer's imagination and sells the scene.
The transporter accident scene in TMP is another dark and edgy scene.
Those are just off the top of my head.
Dark and edgy doesn't have to be on the graphic level of
Game Of Thrones. It's a matter of situation and execution.
Alien stands as one of the great SF/horror films and yet you never really see the xenomorph tear someone apart. Light and shadow and sound and staging as well as suggestion is used to great effect, and except for the chest burster scene we see very little graphic violence. The film deftly plays with our imaginations.