The Stig wrote:
Uhura 'lost out' because the character was written as a glorified extra from the start. Nothing more, nothing less. Nimoy and Shatner's egos had nothing to do with it.
Not quite. Grace Lee Whitney was the female lead but Uhura had a few character moments in Charlie X, the Man Trap, and the Naked Time. There was more of an ensemble feel to a fair few of the early episodes.
When they switched down a gear she benefitted from the loss of Whitney and joined a handful of landing party missions but I agree that most of her appearances involved her sitting in her chair mouthing off a few lines. She's fairly impressive in Mirror Mirror. It would only have taken a few tweaks to a few plots to utilise her far more effectively throughout the series but in the sixties a black woman wasn't going to be put in charge of the ship let alone a landing party.
I do think that the movies did her character no favours though. Her part in STIII was cool but they should have shown how crucial she was to helping the ship escape, scrambling communications and escaping from Starfleet security to seek asylum at the Vulcan Embassy.