My oldest daughter, 14, loved STID. She never saw "Space Seed" or TWOK before STID. Cumberbatch is her Khan and she's cool with it. Might was well try to explain to her why the TOS Khan looks different than Cumberbatch. It works both ways, after all. Further, why would it add anything to the story to use precious screen time try to explain the difference in Khan's looks? Might as well take a moment to explain why nuKirk has blue eyes, too. And let's not even start on Chekov. Where is the line drawn?