Frankly that how shall I put it. That is rubbish.
There is almost nothing event wise that has happened in NuTrek that hasn't happened in much earlier Trek. There are only a handful of differences.
The 1st being the majority of TOS ended with a light hearted moment on the bridge, even if thematically was completely out of place to the rest of the episode, only a few didn't do this.
2nd as the decades have gone by the change in language and what could be shown to a regular audience has changed. It's no longer the days of gunfights with nary a sign of blood or injury afterwards. And of course not only as standards changed but the ability to visually tell a story has increased dramatically. So instead of talking about say whole planets being destroyed, you can actually see a visual representation of it. Instead of seeing a ship get attacked and hear that hundreds are dead, but only see a model perfectly still intact. You can show visual images of seriousness of the assault.
3rd the length that shows use to tell stories has changed from 53 minutes in TOS to now typically a season (regardless of how long that season is be it 22, 15, 13, 10, or shorter episodes.
Now picture a story like the Doomsday Machine being made into a ten episode story. That was a very dark episode, Captain having to listen to his entire crew dying, him being forced to witness it without being able to do anything to prevent it. A weapon destroying planetary systems one after another. That Captain obsessed with vengeance to the point of nearly getting another crew killed, and then eventually killing himself. With the crew of the Enterprise absolutely convinced of the serious nature of this threat and the risk to billions upon billions in its near path, and only towards the end does the crew get a glimmer of hope. And the means to make an attempt to stop it. And finally ending with a moment to discuss how Earth nearly made the same mistake.
Now there are some light hearted Star Trek episodes from pretty much start to finish but they haven't been the norm. And it's true we have never had a season arc that is light hearted from beginning to end, that's one real difference. But we really didn't get a ton of those episodes.
The Majority of the episodes of Trek is crew responds to something, often times something very serious and dark, when you actually thank about what its referencing, and over the course of the episode, the crew generally feels some doubts, but eventually marshalls together or even individually to overcome the crisis and give an uplifting speech, that attempts to show how progress coming together, and getting over differences is a good thing. Thats almost exactly what happens in the story arcs in modern Trek, they are just stretched over a much longer canvas.