The Single Biggest Mistake Each Star Trek Movie Has Made
2. Star Trek Into Darkness - John Harrison
The Mistake: Take your pick really. John Harrison in general. Fine. Let's go with that.
Why?: We all knew this was going to be Khan. I knew it. You knew it. The neighbour's dog knew it. Still, the film decided to make this a reveal. While this is not nearly the worst crime in this film, it just feels far too forced, too desperate. John Harrison could have been an engaging villain in his own right, exploring the dark side of morality and motivation.
The name of the character aside, the fact that he has super blood that can prevent death immediately renders all other points moot. Kirk is killed while saving the Enterprise. McCoy, having already effectively shown that he was experimenting with Khan's blood on a Tribble for no apparent reason, watches the creature come back to life, then eurekas his way to the bridge.
Khan is captured, Kirk is zombified and the day is saved. Never again will Starfleet face any serious threats as their entire armed force just became immortal. The fact that this is then dropped and never mentioned in Star Trek Beyond feels like a retcon, which makes it all the more obvious here.