While Ricardo Montalban was a European immigrant, he lived in Mexico, identified as a Mexican, and faced a level of discrimination that Cumberbatch never had to deal with (nor did white male British actors of Montalban's era either). Montalban briefly discusses some of the hurdles he faced and his feelings about the lack of positive portrayals of Mexicans in this video.
He talks about leaving the US to go back to Mexico due to the lack of roles for Mexican actors around the 10:40 mark and he talks more in depth about Hollywood's negative portrayals of Mexicans around the 18:45 mark. Now, I'm sure some might reply well Khan isn't a Mexican character. Of course that is true, but that's not the issue I'm getting at here. I think the issue is that Montalban had limited opportunities due to his ethnicity being different enough, not WASP enough, that he had to leave the US for a period. This is something I haven't heard any white British actors-then or now-have to contend with and certainly not for the color of their skin.
So while Montalban might be ethnically closer to Cumberbatch than the character he played, he was a person of a darker hue, and he faced hurdles due to that that Cumberbatch or a white male actor of his era would not. Heck, I might be ethnically closer or genetically closer rather to many whites than I am native-born Africans-but that doesn't mean I might be treated the same as whites in this country. And there's a lot of information on racial disparities that would likely show how that is.
And before someone rejoins that Montalban's issues were so long ago, I recommend they check out this link.
Further, I was reading about recent criticism of Eva Longoria's Devious Maids TV show.
The issues of negative portrayals plus overall access to roles still plague Latino actors decades after Montalban raised many of these same issues. Even some of the stereotypes he points out in the video are the same ones that fall under the common Latino stereotypes and it shows how little that has changed.
Where am I going with this you might ask? It gets back to the idea of having more people of color in movie/TV roles than less. There was no need to whitewash Khan. Khan was a major character in sci-fiction, one of the best roles ever played by a person of color in a sci-fi film, heck, in a film period, and it could be an inspirational thing, a point of pride to many people. Further it hinted at the idea that a superman, a human that's the next level isn't a WASP male, which was subversive back in the 1960s and even today. While one might say that Cumberbatch's turn could do some of the same things, it likely won't since we have tons of white male actors in all kinds of roles on TV and in the movies. Did a white actor really need to be Khan too?
As for the evil brown guy terrorist thing, part of the concern there is how Into Darkness wrote Khan. They made him more of a contemporary terrorist than he was in "Space Seed". He took on some terroristic (sp) actions in "Wrath of Khan" but that was more of a kind of space opera/space adventure sort that didn't echo 9/11/War on Terror. If anything Khan was a product of residual World War 2 fears and it was Abrams, etc. that decided to turn him into a War on Terror analogue.
Since Khan's character was established long before as a person of color I don't think the concerns about having a person of color play him in Into Darkness were going to whip up any frenzy.
I agree with how the blogger Arturo said that smart writing could compensate for whatever possible negativity might occur from having a browner actor play Khan in Into Darkness, from the Racialicious website.
"The point was raised, astutely, by several commenters in Monday’s thread that casting a South Asian in the role ran the risk of taking the character into problematic territory from another direction. But I continue to feel that having the franchise’s seminal villain resurrected with appropriate casting and smart writing might have mitigated those concerns, at least partially."
I think these paragraphs, from Racebending. com says it better than I can:
"But all of that will be marred by having my own skin edited out, rendered worthless and silent and invisible when a South Asian man is portrayed by Benedict Cumberbatch up on that screen. In the original Trek, Khan, with his brown skin, was an ‹bermensch, intellectually and physically perfect, possessed of such charisma and drive that despite his efforts to gain control of the Enterprise, Captain Kirk (and many of the other officers) felt admiration for him.
And that’s why the role has been taken away from actors of colour and given to a white man. Racebending.com has always pointed out that villains are generally played by people with darker skin, and that’s true … unless the villain is one with intelligence, depth, complexity. One who garners sympathy from the audience, or if not sympathy, then — as from Kirk — grudging admiration. What this new Trek movie tells us, what JJ Abrams is telling us, is that no brown-skinned man can accomplish all that. That only by having Khan played by a white actor can the audience engage with and feel for him, believe that he’s smart and capable and a match for our Enterprise crew."
I enjoyed this whole piece, "Star Trek Into Whiteness" from which the abovementioned paragraphs are taken.
Finally, on to Uhura...
I can agree with you that Spock was the breakout character on TOS, but I think it debatable that Kirk and everyone else revolved around him. Kirk was a pretty well developed character without Spock and part of Spock's greatness derived from his interplay with Kirk and McCoy. If Spock was so essential why would they eventually start looking to do the aborted second TV series without him? It's likely Nimoy didn't want to come back, but that didn't stop them from going forward with the show and casting a new Vulcan. Further the success or at least the continuation of the 24th century Trek shows were largely done without the involvement of Spock and all three lasted several seasons longer than the original.
Now regarding Uhura, despite the wonderful work that has been done to make her character more important she is still too defined by her relationship with Spock. You can't refute that, so you posit that everyone else is defined or revolve around Spock. That does nothing to support the idea that Uhura can stand on her own without that relationship with Spock. If anything, your argument reinforces it, maybe even endorses it.
As for the essay you posted regarding the relationship before, I thought the writer made some good points, but I don't necessarily see Uhura being in a relationship with Spock as any more empowering than being single. I do think the relationship gives the character more screen time and attention and it is a good thing to see a black woman being portrayed as smart, capable, and desired by arguably the most popular character in the movie and one of the most popular in sci-fi. But if her relationship with Spock ended tomorrow, where would this character be? Because a lot of the screen time she has gotten thus far usually has her pissed, making googly eyes or fretting about Spock.
If I recall correctly I read somewhere that Saldana said she didn't think Spock and Uhura were going to last. So it will be interesting to see what would happen with the character if that happened.