The scientific MacGuffin of Khan is that some Federation-funded scientists have developed a missile that could create life from death. Its got an old-school scifi theme of men usurping the godly powers of creation, and its just dangerous enough that getting ones hands on it is something people would die for. The way it works is that you fire it at a planet and it erases all the life on that planet and re-starts the evolution of life. Im not saying that makes sense. It doesnt make sense at all. Its a bit clunky on the godly powers theme, and the science is pure technobabble. But its a relatively simple concept that an audience can digest quickly enough to watch and believe the unfolding drama. Into Darkness is just all over the place with magic new technologies. Theres the statis pods that Khan and his friends were frozen into, that were then made to look like torpedoes. Theres the thinly veiled drones. Theres the new super-powered starship. Theres Khans blood that can magically bring people back from the dead, or from the brink of death. ITS TOO MUCH. The technologies trip over each other, the plots run into each other headlong, and the drama is undermined by an overabundance of MacGuffins.