Sorry to hear it doesn't work for you. I thought she provided more of a moral voice, very similar to McCoy's role in TOS, as well as her relationship with Spock.
I especially loved her negotiating with the Klingons. I thought it was very well done.
Uhura is in the movie to supply emotional support to the guy with no emotions by yelling at him for not caring enough about her when he just almost died. That's how it looks to me. Her part with the klingons was nice, but ultimately pointless.
Um, quick point-Spock is not a guy with no emotions. The whole point of Spock, from Nimoy to Qunito, is that he keeps his emotions under tight control. There was a miscommunication as to his nature and that needed to be addressed. Based upon Spock's discussion in STID I would say that the problem has been going on for a year and it reached its head with Spock deciding that he wanted to die in the volcano.
That's how it looked to me.
not to mention that it's basically the only scene in the whole movie where the aftermath of what had happened to Vulcan, and Spock, was somehow finally addressed (hello continuity, because, after all, this was supposed to be still a sequel of the first movie) and you get a glimpse of what it means for Spock to be a vulcan (which goes beyond the 'no feelings just logic' stereotype) and the fact that, actually, vulcans feel deeply than the humans. I could argue that it's the only personal scene in the whole movie that is just about Spock, one of the supposed protagonists you know, and his own story. If you remove that (or the first movie for what matter), he's back to being just the nerdy friend of hero and a sidekick for Kirk (I wonder if this actually is the problem some people, especially Kirk fans, have with S/U and why they resent Spock having a life outside of Kirk
so much, but have no issues with having more than one dynamic with and for Kirk)
Kirk being there also made him learn a tiny valuable lesson about the fact that some members of his crew are not human (or not just human) and, perhaps, him whining about Spock essentially being himself was detrimental to his attempts to be his friend, not to mention him possibly getting a reminder of what the other guy was going through, which he seems to completely not take into consideration even though one presumes this is what a friend would do (and, again, maybe he shouldn't have even asked Spock to participate to either mission due to the possible still lingering psychological repercussions of the vulcan diaspora on him)
Uhura also saved both Spock and Kirk in the end.. and she is the one who made the little skype chat between Spock and Spock Prime possible when communications were, courtesy of admiral Marcus, completely down between the enterprise and .. the galaxy.
She and McCoy also were the ones who helped Spock tricking Khan about the torpedoes, and she also co-piloted the shuttle with Sulu at the beginning, and was the one who monitored and then told Spock through the captain that his device in the volcano got successfully activated and the planet was safe. Because even when her man was possibly dying and she was terrified, she still did her job and she didn't even run to the transport pad with Kirk and McCoy, she asked the captain if her man was alive from the bridge
while giving her report. (What were McCoy and Scotty doing on the bridge beside worrying for Spock, again?). But all these things are irrelevant

after all, the rest of the secondary characters did all this super interesting stuff and were so useful for the plot...
I wonder if things would 'look' differently for
ancient had Uhura been 'Uhuro' and the relationship with Spock was just another dudebro dynamic to add the the list..
sure, when you have a franchise like trek, where the story is set in a futuristic context and where humans interact with other alien species/races, how crazy for the writers to try to show the different interpersonal relationships between those different characters, and try to imagine how society would be in such scenario.
Clearly, turning it all into a monastery and ostensibly keep everything 'platonic' is the only way to go and the most interesting and realistic course of action..
and of course, the 'dudebro' dynamics between men are never enough but the ONE different kind of relationship (for a change) is off topic and unnecessary..
btw, Uhura also acts as a friend to Kirk (and, God forbid me, their dynamic actually was far more believable to me than even the friendship between K/S,
anyway. )
The Kirk/Uhura/Spock trio is not a triangle, it's 3 characters showing 3 different kinds of interpersonal relationships: friendship between guys, friendship between a man and a woman, and a romantic relationship between two people who happen to be in love despite the fact that one is a half vulcan/half human hybrid and the other is human.