Been thinking, with all said and done and the supposed renegade Starfleet officer John Harrison revealed to be Khan, I've come to realize, I was more interested in the fiction of the John Harrison persona than I am in Khan. Khan's been done, and while STID didn't retread Space Seed or TWOK with what they did with Khan, doing something completely new doesn't hurt either. In all honesty, I believe the movie could have been improved had the villain actually been Commander John Harrison, renegade Starfleet officer turned terrorist fighting for ideology instead of Khan taking revenge out on an Evil Admiral.
And the movie wouldn't have to be changed that much. Harrison could still rip the transwarp beaming to go to Qo'nos. If they made his backstory some sort of Starfleet special ops badass that could explain how he'd last against the Klingons, and from there you can still have Evil Admiral Marcus wanting Harrison out of the way and making it personal. Kirk still decides to work with Harrison board Vengeance, Harrison still betrays Kirk and kills Marcus. No magic blood means Kirk couldn't die and therefore That Scene wouldn't have happened (I'm fine with that). It is kind of unlikely a regular human could have survived Vengeance's crash, just say Harrison somehow managed to transwarp beam out, so he's still out there, just not an immediate threat, which is basically the same situation we have with Khan.
Hell, all making the character Khan did was possibly make thing marketable, but then Khan was a secret so the movie didn't really captilize on that marketing potential, and even now the cat's out of the bag it isn't exactly bringing in money hand over fist.
So what does everyone else think? Would John Harrison be more interesting than Khan?