Spock is a unique figure in Starfleet, as much as Worf or Data are, even if not so wholly unprecedented or influential.
To quibble, the whole "first Vulcan in Starfleet" thing is fanon. In fact, it's canonically wrong because TOS has an entirely Vulcan-crewed ship.
Isn't Kirk like supposed to be one of the youngest to ever sit in the captain's chair? He's definitely a maverick.
I'm pretty certain this wasn't actually established while TOS was airing though right? Again, it's a later puffing up of Kirk as a character.
DSC started and finished a Klingon War. A war not quite as quadrant-spanning or as large in scale as the Dominion War. So I won't call this an increase in epicness. I completely ignore and disregard ENT. And VOY does not increase epicness from DS9. So, basically the increase stops at DS9.
I mean, you could point out that the Mycellial Network threatened to destroy all universes but it didn't and no one watching thought it would. So that threat meant about as much as the Omega Particle on VOY, which was also stopped.
I was thinking more about how Micheal Burnham's personal arc was more epic/heroic than anything seen in Trek before. I mean, consider everything:
1. She was adopted by Sarek, and raised as Spock's sister
2. She served as the XO of one of the five most decorated (up to that point) captains in Trek history
3. While she didn't actually cause the Klingon War, she was blamed with doing so by Starfleet. She did directly murder T'Kuvma however, who was at that point the closest that the Klingon Empire had to a titular leader.
4. She then began service on the most technologically advanced ship in Starfleet, which could (as we discover) literally travel anywhere instantaneously. Any point in space and time, in any alternate universe.
5. She enabled the Discovery to finally destroy the Klingon Ship of the Dead, killing Kol, who was again, all but the titular leader of the Klingon Empire and their assault on the Federation.
6. When we get to the MU, it turns out that the evil doppelganger of her deceased former captain is, quite coincidentally, the ruler of the Terran Empire.
7. Both Ash and Lorca had secret identities and were in love with her.
8. She ends up winning in a very contrived manner - essentially setting up a scenario where all of Starfleet is wrong about something in order to ensure that she can be the source of moral rectitude. But as part of her victory she installs the only other Klingon we've been on a first name basis with - whose been rotting in the brig of Discovery for weeks - as the new Chancellor.
As I said upthread, across the whole of DIS maybe 13 characters (including MU alternates) actually had any sense of agency to them. It was a weird contrast - the epic scale yet the same small group of people being responsible for absolutely everything.
I do want compelling characters. But just doing their jobs? I'm not a fan of working-stiffs in space... unless it's Alien, but that's because it's set-up before the Xenomorph is sprung upon them.
There's a reason so many of us found O'Brien relateable.
Along with the epic stakes rising, is the disaster porn. I noticed a lot of large scale disasters and destruction that increases with each series.
TOS started with the Eugenics war which killed 30 million. DS9 has the Breen attack earth. TNG makes WW3 a separate incident, 600 million killed. The Cardassians are decimated by the Dominion, close to a billion. The Xindi from Enterprise appear out of nowhere, and attack earth, 7 million.
Then the JJ movies has the entire planet Romulus destroyed, and later Vulcan.
The problem with all this is, the more destruction they showed the less I started reacting to it later. By the time they showed the Xindi attack, Romulas and Vulan being destroyed, I had almost no reaction.
I know I was supposed to, but so much of it was piled on at that point, that I just didn't.
Human psychology is not just set up to feel empathy on a massive scale. It's why the refugee crisis in Europe didn't really break here until the photo of a single drowned toddler on the beach. We can't comprehend the deaths of tens of millions as anything other than a statistic. But if we see one dead child - just one - it reminds us of our own, or our grandchildren, or our nieces/nephews, etc.
As I said, ultimately the best stakes in fiction are personal. Even when the protagonist is a classic hero who is on a journey to save the world from the forces of darkness, the core of the story is the emotional involvement with the hero, not with the stakes of the wider fictional world. If you don't create a compelling hero - someone we empathize with - all the disaster porn in the world won't change things.
It's a sci-if action adventure series. It's not "The Piano."
It's also not real. It's entertainment...entertainment about extraordinary people doing amazing things. I don't want to see Captain Bill Smith and the adventures of the unremarkable USS Milktruck, a standard light cruiser with nominal technology and a plethora of currier assignments.
It's supposed to be fun. Not realistic.
Again, part of my criticism is the bigger you make the characters, the smaller the world they inhabits seems.
I mean, TOS had that amazing feeling of expansiveness in part because of what you don't see. Enterprise doesn't ever go back to Earth. There are run ins with the Klingons, but never anyone seemingly higher than a mid-level functionary. You never see an admiral more than once. You never even get a clear idea of the membership of the Federation. All of this paints one Starfleet ship - even a Connie - as a pretty small cog in the wheel.
Trek has slowly lost this sort of feel over time. A significant portion of that is because the writers don't understand when it's better not to show things, and always want our characters to be at the center of the action, rather than bystanders. While the least "epic" of the shows - VOY's ruining of the Borg is a great example of this. They were truly menacing when first introduced in TNG. But as VOY began treating the Borg Queen more as a singular consciousness obsessed with Janeway, the Borg became steadily diminished.