Spock, Kirk, McCoy. The three Amigos. BFF's. The orginal bromances. Or as I like to call them, the holy trinity of Star Trek. They were the formula for the friendships that were formed among later casts in the franchise and any person, even if they aren't fans of the series or movies can name them and their roles in the show.
If the three represented aspects of humanity, this is what they would be.
Kirk: The body. Kirk survives on instincts and his passions. Danger? Love it. Passionate love making? Right there. Kirk does everything big and his only regrets are things he hasn't done big. If there were a picture in the dictionary of the id, Kirk would be it.
Spock: Mind. His intelligence is unequeled. His curiosity insatiable. He does not let emotion cloud his judgement on decisions he believe must be made for the betterment of the ship and his friends. Sometimes he is so cold and calculating he is compared to a robot, although his emotions are there deep under the surface.
McCoy: Heart. McCoy wears his emotions on his sleeve and he lets them get the better of him from time to time. This causes conflict with Spock, whose cold calculations brush against McCoy emotional outbursts. McCoy compassion, crankiness, and over all emotionality round out the chemistry of what made the original series and movies work.
Kirk was the center of this trinity. He weighed the arguments of heart and head within himself to pick the right choice in order to save the day. Spock and McCoy fought and he listened. They both curbed his natural instincts for pure passion and danger and he in turn made them live a lot more than they would have on their own. But the trinity was balanced towards Kirk as the big main character of the series. So ultimately the power belong to him and everyone's reaction to him.
The new movie changed this. Spock was no longer the mental foil for Kirk's escapades but a main character that was just as emotionally rich and dynamic as Kirk. In some ways, his emotional and mental journey is bigger than even Kirk's as he deals with the loss of his planet and his parent in short succession. This balances the narrative. It is no longer about Kirk and his journey's with the Enterprise. It is now Kirk and Spock's journey with the Enterprise. One cannot go without the other. They are now equal in ways they were not in the original series.
Enter Uhura. While I agree with the aspect of criticism that her role as a sex object to Kirk takes away from a much needed narrative of a woman who should be valued for her work and expertise, I do disagree that her place has been demoted in comparison to the new series. While this movie changes the power dynamic of Spock and Kirk, it also rounds out the trinity that has been in effect since the beginning of Star Trek. The trinity is no longer the Trinity, but some type of super square. lol
McCoy, presented in this universe as Jim Kirk's best friend and academy buddy, still occupies a place he held in the series. He is still a confidant to Kirk and centers Kirk where he needs it. His role is to be Kirk's sounding board and a partner in his emotional mischief. He no longer serves as a counter point to Spock, but he does serve the heart equation of the center relationships of the main characters.
Uhura serves the equal of McCoy in this universe and this is a big deal. While McCoy evens out Kirk with some rationality, Uhura evens Spock out with her emotionality. She becomes Spock's emotional center in the midst of absolute chaos. Spock is no longer the super rational man he was in the Prime Universe but is someone who is embracing his humanity in ways that Spock Prime never could. While Spock Prime dealt with his emotions with trying to suppress them to ultimate logic, this Spock finds himself embracing emotions he never thought he would have to, which makes his relationship with Uhura just as important to his development as McCoy's relationship with Jim is to Kirk's development.
To say that this is a big development is to be an underestimation of what is going on here. It is a fundamental change in the dynamics of Star Trek lore, not just because Uhura is Spock's girlfriend, but also because she is now in the inner circle of the main three. She is shown strong enough to be there. She out thinks Spock in getting her assignment on the Enterprise. She is not weak in the knees to Kirk's sexual advances and therefore is shown to be immune to his legendary charm. She can be as compassionate and have as big of a heart as McCoy. She is smart as a whip and doesn't take anything off of anybody. She has her beliefs, her own moral compass, and an ability to be the best at what she does.
I'm curious to see where this goes in the sequel and what these new dynamics means for the future of Star Trek.