1. Why use Khan again like in Star Trek 2 and why use the identical death-sacrifice of Spock only with Kirk doing it?... This recycling of old ideas is a bit lame. A bit more creativity and original ideas could be expected.
2. When they let Kirk die I first thought: "WTF, they really mean business this time and let the captain die, what an awesome "We don't give a f..."-moment, similar to the effect the destruction of Vulkan had in the first movie. But then they got all whimsy about and backed off, saving Kirk's life again.
3. Khan used Scotty's transbeam-technology to beam to Cronos, and when Kirk got there he instructed Zulu to give a message to Khan that he should surrender... What the hell? How stupid is that? Giving him notice of their appearance and warning him only would have caused him to use his transbeam-technology again and beam anywhere in the galaxy or into the Enterprise and doing either all kinds of damage or get lost again. It was a totally destroying the plot-moment.
4. Khan hid his crew in those rockets? Why? Did he really think he can walk out with those rockets, did he really thinking no camera would catch him hiding them there? Again a major what the f...-idea.
5. Khan taking revenge on the admirals was all nice and well, but then what, what was his plan? Simply going to Chronos and doing nothing? He had no plan, he just beamed to Chronos and did nothing till Kirk captured him, From a calibre like Khan I would expect making big plans and not only simply taking revenge and be done with it.
6. And what was that with Spock screaming "KHAAAAAAAN" like Kirk did in star trek 2? He completely gave up all of the decades-long-training of mental control he learned on vulcan... Didn't make any sense at all.
But there were things I really liked:
1. The destruction of Vulkan and the disappearance of the influence of the peace-loving vulcans and the near destruction of earth in the first movie of the reboot, caused the military to gain much bigger influence. I really liked to see that play off, all that military control and conspiracy and the tenser atmosphere.., and I loved seeing the actor of "Robocop" back in a big movie...
2. I loved the humour all through the movie, especially around Scottie.
3. The action was nice, Khan's martial arts, all the explosions and star ships crashing on earth... the flying through space in spacesuits-action.. good stuff.