But since they went the Khan route I think they should've cast a nonwhite actor. I think Khan is popular enough name/brand/character, if not his actual story, that it trumps him being a run of the mill brown skinned terrorist.
Plus Khan being a villain with some positive traits might have also undermined the dehumanized stereotype. Perhaps having a person of color back as Khan might dredge up those kind of vile feelings, but it might also present an intelligent, formidable brown skinned person that fans can possibly admire and understand. That might have changed perceptions in a way of turning Khan into a white guy, which avoids the issue, have not done.
You could well be right. After all, Harrison/Khan wasn't the real terrorist here; Marcus was. At least until the climax, he was a relatively sympathetic antagonist, acting to defend his people from the real monster, Marcus, who was trying to use them to start a war. That could've been a nice way of subverting terrorist stereotypes -- to show us a dark-skinned guy who seems to be a terrorist and then turn it around. Although that would've worked better if they'd left out the massive urban destruction in the climax -- but then, they should've done so anyway, because it really didn't contribute anything to the story.
I don't agree, actually -- I think the attack on San Francisco was thematically important, because it established a link to the issues of terrorism in the modern world.
To wit: Al Qaeda grew in strength and sophistication to the point where it was able to attack the United States on 9/11 because the United States had provided so much assistance and aid to the anti-Soviet mujahideen
forces in the 1980s; al Qaeda then built on the weaponry and organization these movements had developed, recruiting and growing. So 9/11 was the unintended blowback of the U.S.'s involvement in (and subsequent abandonment of) Afghanistan.
The attack on San Francisco parallels this. Khan is unleashed by Admiral Marcus and Section 31 in their bid to militarize Starfleet and launch a war against the Klingon Empire that they can claim is "justified." When Khan turns on them and attacks San Francisco, this is the unintended blowback of their decision to try to use Khan against the Klingons, in the same way 9/11 was the unintended blowback of the U.S.'s decision to use the mujahideen
(If anything, Khan's attack on San Francisco should have been given greater attention and weight in the plot -- though the movie was getting a bit long by that point, yeah.)