I expected John Harrison, rogue secret agent with superior abilities. The film didn't need Khan and his 72 followers. It could have been John Harrison and his group of agents held captive by Admiral Marcus.
So we would have had a man with superior abilities, who is out for revenge against a Starfleet admiral and his followers who also have superior abilities who are in cryo-storage for the most part.
So this doesn't sound remotely similar to an already existing trek villain?
With Nero we had a madman who had physically superior henchmen, and who had a doomsday device who was out for revenge.
Nero was a bit of Shinzon, Rua'fo, Soren, Chang, Kruge and Khan. John Harrison wouldn't have been much different from that line of villains. And indeed, nuKhan isn't different either. They are just rehashing the same old bad guy with super weapon is out for revenge plot, no matter what they do and what the villains name is.
Actually I find it funny that people believe the film is somehow elevated by the villains NAME. Change the name BUT NOTHING ELSE and they are suddenly not interested? Essentially you are told what you like. "This is Star Trek, because they call it Star Trek.", "This is a better villain, because they call him Khan!" I find this curious to say the least.