Re: Into Darkness and the novelverse [SPOILERS]
He [Khan] was given a false identity, and as a major historical figure he had a recognizable face. It stands to reason his Caucasian appearance is the result of cosmetic surgery
That's exactly how I rationalised him looking like Benedict, instead of Ricardo. I never had a problem with it. It was one of those things that was so obvious it never had to be spelled out.