This is an odd thing that permeates all post TOS Trek.
On TOS, Kirk was the only one who was shown to be extraordinary, as he had come come up through the ranks very rapidly. Maybe one could make an argument for Spock, but it is unclear if his intelligence was simply average for a Vulcan. Everyone else was competent at their jobs, but nothing particularly special.
Then with the Berman era, with only few exceptions (sorry Worf), almost every crew is composed of genius polymaths, so the newer productions retconned the genius thing to also apply to the TOS characters, presumably since that's what had become the norm for Starfleet crews.
Yes and no.
Scotty was generally portrayed as like, a particularly good engineer, and McCoy was a particularly good doctor.
Although even Kirk gets inflated later on. In TOS, he's just like, a particularly good Captain? Now with Kevlin / SNW he's ALSO a super genius too, because of course he is.
I would somewhat disagree on the TNG crew though. They're all... exceptional in terms of their job, but really I don't think anyone is really portrayed as overly extraordinary just in general.
Picard is... a good captain.
Riker is... a good first officer.
Troi is... Idk, Troi.
Worf is kind of terrible at everything.
Geordie is a... good engineer.
Crusher is a... good doctor.
The only truly exceptional person on the E-D is Data, and that's kind of cheating.
I think in the Berman era, there was an attempt to portray like... EVERYONE in general as being overall more intelligent/more highly educated that most people today.
Meh, it shows how other career paths in Starfleet are completely devalued over time. Enterprise becomes that flagship, crews will not accept promotion to stay on the Enterprise.
Then, it wasn't good enough to just be a good officer but you have to become a ship's captain or a flag officer to demonstrate even better achievements. Only starship captains are the best goals and achievers.
I think that is somewhat clouded by, in general, the "main characters" of the shows being highly prestigious ship captains. If we did an entire show about Deanna Troi, I doubt it's going to be about her strong desire to be a ship captain... you have people like Scotty who expressly did NOT want to be a ship captain.
I think it's a positive thing to show that people can and will not accept promotion to stay on the Enterprise. I think that really shows how Starfleet generally wants it's people to be happy and do what they want to do... if someone is happy in their position on the flagship, and they're doing their job well, cool! Stay there! I think it's exactly the opposite, those career paths are highly valued, to the point that if someone is doing a career they enjoy and they're on the Enterprise... they will actively reject moving onto the "only job that matters captain"...