STID is actually only a "mediocre bad movie". It's not worse than, say, the G.I. Joe movie, or "battleship". In fact, some parts and scenes in it are actually quite good.
It only turns bad once you have some insight knowledge of Star Trek...
I have to disagree on this. The movie might at a very surface level feel like a good actiony movie, but if you think about any aspect of it for more than a second it all collapses into a pile of drivel and little to none of it has anything to do with prior Trek knowledge. When you pile on top all of the things that make no sense Trek-wise (e.g., the Khan reveal), it gets even worse.
[/Rant - written right after I saw the movie that one time, so some of this might be a little off.]
- The one really strong character moment for Kirk is when he apologizes to the crew that he screwed up and they are all going to die - but then they don't, so everything is fine and no one has a learn a lesson after all.
- If it had been done correctly, the emotional scene of Kirk's death and Spock's understanding of friendship would have been really powerful - but these characters have only known each other for about 1 year at this point. These characters are just starting to know each other; this is a one-year friendship ending, not a 20+ one.
- So Spock Prime vowed never to reveal future information? Except when he gave Scotty and all of Starfleet a magical equation for transwarp beaming that allows people to apparently beam anywhere in the galaxy that they would like. And he violates that oath again by telling NuSpock all about Khan.
- So the whole (if small) crew of the USS Vengeance is perfectly willing to destroy the flagship of the Federation and all her crew - who just saved the entire Federation and billions of lives 1 year ago - because they were trying to stop a preemptive war? Where did we recruit these sociopaths?
- So Section 31, the most efficient and most secret intelligence organization in the galaxy, was able to build a giant complex underground in the heart of London with no one knowing, but then their giant ship construction yard out in space is so totally unprotected that a lone and fired officer with no information but a set of coordinates wanders into it, gets onboard their megastarship and sabotages it?
- So the Flagship and the Vengeance have a firefight in space, basically in orbit of earth. Two issues with this: first they were traveling at warp to get from the edge of Klingon space to earth, but they only were at warp for about 20 seconds because right after they jump to warp, Kirk is warned that it won't work because Marcus has advanced warp drive and weapons and almost before the warning can be completed, the Vengeance attacks and knocks the Enterprise out of warp. So the Enterprise comes crashing out of warp, totally out of control and totally unexpectedly, they end up only about 200,000 miles from earth. If they had stayed at warp for another fraction of a second they would have either crashed into earth or blown right past it?
Second, where is everyone else? Everywhere is deserted throughout the whole movie. No one shows up in time to stop Khan's attack on Starfleet HQ except a couple of security redshirts. No one shows up at the Klingon border. Only a couple of small, random patrol craft show up on Qo'nos - the capital of the entire Klingon empire. No one shows up to stop Scotty outside the shipyard at Jupiter. Only 1 security officer shows up to stop Scotty in the hanger bay. And no one comes to the scene of this massive Starfleet vs. Starfleet battle in earth orbit?
- What was Marcus's plan? Start a war with the Klingons by getting them to destroy the Flagship of the fleet. So does he accept Kirk's offer to fly directly to Qo'nos to kill Khan and get the war started? No, he has a super complicated plan to get Kirk near Klingon space, have him attack from long range, get stranded and then get destroyed. And how does that work out? The Enterprise is disabled before they even complete their mission. Luckily for Marcus, Kirk manages to violate Klingon space in another manner. Why disable the Enterprise before their mission succeeds? Kirk has no incentive at that time to fire the torpedoes - Khan doesn't even know he is coming until Sulu sends his asinine message. Why (in the original plan) wouldn't they just fix the engines, then fire the torpedoes and not risk getting killed by the Klingons?
- How can you possibly detect and track one man on a planet lightyears away? I guess with new transwarp beaming you can do anything. So, why, once Kirk decides to capture Khan, do they not use the transwarp equation to beam him up from Qo'nos? Clearly any regular transporter system can be quickly and easily modified to do the job (as seen in Star Trek 2009)? And apparently the equation is simple once you know the trick. It takes Scotty about 2 seconds to understand where his existing formulation had been incorrect.
- Kirk, via general broadcast, warns Khan that he is coming. Maybe. Kinda. He apparently has Sulu broadcast a message directed at an entire random province of Qo'nos. Does Khan have a communications device? Unknown. Will Khan receive the message? Unknown. Will Khan care about the message? Unknown. Isn't giving the fugitive very advanced notice that you are coming to arrest him really stupid? Wouldn't he be able to then hide, get on a ship, transport away, block your sensors, or any of a dozen different things?
- Well, how about why does Kirk order the warning transmission? Does he think Khan will give up? I guess so. Someone who bombed a major Earth city, attacked a Starfleet HQ session killing many people, who then beamed to Qo'nos to apparently live a life on the run amongst bloodthirsty Klingons - I am sure that person is just going to give up when you say you can possibly, maybe kill him with torpedoes sometime in the future, if he doesn't run away, if he hears you. Or if Kirk is trying to be honorable about this "arrest" by broadcasting a warning first, why is he ok with just violating Klingon space which could trigger a war?
- And coincidentally, they haven't even gotten to Khan when they are attacked and forced to land by some Klingons, and somehow despite how large the province likely is, Khan shows up on foot within about 3 minutes of them landing. I got over Kirk, Spock Prime, and Scotty running into each other on Delta Vega in Star Trek (2009) because it was fate bringing them back together, but fate also decided that Kirk and Khan needed to meet on Qo'nos?
- So Kirk flies in, destroys three or more patrol ships and crews, and gets out; no Klingon ships follow up on this attack, no one tracks him. The Enterprise is hanging there is space, immobile for a long time and nothing happens? If Kirk had fired the secret, special long range torpedoes, as per the original mission orders, no Klingons would have apparently come then either. And how could Marcus get revenge on Khan via the torpedoes, when they would likely only launch 1, killing only 1 augment. Why would Kirk ever fire all 72 torpedoes at Qo'nos to kill one guy?
- So what was Khan's plan? Based on his dialogue with Kirk, he tried to smuggle his crew away from Section 31 by hiding them in the torpedoes. With that amount of access, he could have woken them up or simply taken them away, but instead he goes to all the time and effort of swapping out the internals of 72 super torpedoes and replacing them with cryo-tubes. This has to be the stupidest thing I have ever heard of. When he is discovered, he is led to believe his crew was killed and he escapes. He blows up Section 31 in London, then attacks Admiral Marcus and escapes to Qo'nos. But he didn't even manage to kill Admiral Marcus! He could have transported into the building and walked right up to Marcus at any time and shot him and them beamed out with his backpack-sized transporter, but he didn't. And when he has failed in his mission to kill the one person he most wanted to kill, then he just runs away without trying again?
- And why does he run to Qo'nos? Because the Federation cannot go there is the stated answer. How convenient, the one place Admiral Marcus wants to attack. Why didn't he go to Romulus or hundreds of other worlds outside of the Federation that Starfleet can't get to? Why not simply transport to the farthest place reachable so no one comes for you? This coincidence makes it seem like Admiral Marcus was still manipulating Khan's actions. So either Marcus is a terrible war planner and can't manage to get this war actually started (which we already knew) or Khan is a terrible assassin and doesn't care that he failed.
- At one point Kirk orders Khan moved to sickbay? Why? No reason. He tells Marcus that Khan is in engineering. Why? No reason. Does it matter? No. Khan just sits around in sickbay for a while. What is his goal? Nothing, he just sits there. What is his long term goal? Apparently to sit around until Kirk decides that they need to go on an away mission to the Vengeance which, luckily, he can take over as it is the only ship that can be manned by a very small crew compliment.
- Carol Marcus does nothing in the whole movie. She shows up and tells Kirk only things that he gets also from Khan. She doesn't even know as much info as Khan does about the torpedoes, nor are her skills needed to open the torpedo; McCoy does that. She doesn't even know the first thing about them until she scans them. Also, she claims she knows everything about her father's technology developments. If that were true, that would include Khan and his backstory because that is the source of the new weapons tech. Except she doesn't care about any of that - none of the coercion or hostage holding, none of the secret military ship building, or plotting against the Klingons. She either knows nothing about any of it and is thus useless, or knows all of it but doesn't care. So why is she here again? Oh yeah, to take off her clothes for no reason.
[/end rant]