Nichelle Nichols said that they were
just friends (
source). I also remember she once mentioned their dynamic was inspired by her affection for the actor and her concern for his health.
Reading the novelization and watching the movie, I think the original point was hinting that Uhura felt alone and she had regretted making her life about a career only. So when Sybok raised up those feelings, she projected them on one of her friends. Because the movie doesn't have great writing overall, and her character was honestly neglected, the whole point became too subtle and more like a missed opportunity to address an issue that all the characters had.
It's the one thing I don't like about the movies, making them all married to a job and getting old without showing a personal life that matters too? Not realistic. At one point, almost cruel and pathetic too especially when Kirk gets a son out of nowhere but, of course, they kill him asap. Cannot let him have something, anything, outside that ship.
Racism.
And when it comes to tos, 60s flavored sexism in all its glory.
I disagree. Kelvin Uhura wastly was an improvement and upgrade of original Uhura. And her sass is just
fine.
She had agency in all movies, in and out of her dynamics (eg in st09 and stid when she called Spock out on his shit). I have issues with Beyond completely erasing her pov in the relationship, though, and their making Mccoy the one who mentions she maybe was 'upset', which isn't giving a female character agency but falling in the sexism-disguised-as-feminism trap of thinking that if women express their feelings like guys do they are annoying, naggy, bitches. Dehumanizing women to make them 'strong' to disingenuos fans with double standards isn't genius, it's just lame.
But at least she still has an important role in the story. Her being competent and badass is a constant in the movies, and the fact she is finally allowed to have a personal relationship is a much welcomed plus.