I just saw a curious new ad for STID on TV. All about Harrison and his "better"ness. It all but comes out and says his name and shows far more of the Vengeance crash. Someone who hasn't seen the movie turned to me and said "Oh, guess I know who the bad guy is now..."
It seemed like a reactionary ad based off some of the negative word of mouth about unnecessarily obfuscating the villain and belays some panic about Memorial Day Weekend movie traffic.
I know I'm seeing it tomorrow, so I'll be curious to see what the traffic is like.
Honestly, if you're a Trek fan, it's been obvious from the trailers. Hell, IMDB has had John Harrison/Khan for months.