I am glad this subject was brought up, because when I was going through TOS a few months ago, I was rather shocked by how Spock was treated at times by his subordinates. I can't point to any specific examples that haven't been noted, but I certainly got the impression that the writers never agreed on Spock's role, or the relationship between Vulcan and the Federation.
Take, for example, that McCoy said early on the Vulcan was conquered, implying that the Vulcans didn't enter the Federation voluntarily (though this is debatable). I recall it being mentioned later in the series as well.
Spock's race was sometimes Vulcan, sometimes Vulcanian. It wasn't simply a matter of them not settling on a name until later in the show, as Vulcanian was used in the third season as well.
To be fair, it wasn't that the writers 'couldn't agree', as the writer's had little to no control over - barring interminable re-writes against a ceaseless count-down - of what gets approved through the production process and what does not, and what actually ends up being broadcast - just ask Harlen Ellison, he'd love to explain it to you; being rumored to be a somewhat verbose fellow.
Again, the so-called RACISM between the characters was present in 1966 STAR TREK because Roddenberry meant it to be there
, that's the only reason why the characters behave the way they do - and he was subtly TRYING to tell you a something other than _____ism is bad.
Sadly, that subtle message (warning) has been purposely TWISTED and REPLACED in later 'versions' of the show with a wholly different and antithetical message.
Sad, but true, even the 'Great Birds' eventually get trapped in cages on the Prison Plant,... and submit to the might agenda,.. that is if they want to work in Hollywood.
Sometimes they just quit,.. sometimes they end up doing both.