Go watch the unloading scene. Let me know if you see anything that might be a launcher. If not, they were there already. Of course Scotty knew the mission. It was him who figured out where Khan escaped to and how. There's a huge difference between having the ability to fire a ton of torpedoes and perform an execution with them. We saw weapons from one spot in TOS, but dialogue spoke of more torpedo tubes and phaser banks than they could afford to show. Come "In a Mirror, Darkly" and modern CGI, and the USS Defiant has many more weapons than we ever saw the original Enterprise use. And aren't those phaser turrets the same as those on the classic movie Enterprise? Yup they are. Seems more like the fans who read into it with the issues... See my point about the Constitution-class Defiant in "In a Mirror, Darkly" - the script needed aft-firing phasers and torpedoes, so we got them. Ditto TOS-R "This Side of Paradise", where the ship sprouted bomb bay doors to deploy satellites. DS9's Defiant sprouted an entire shuttlebay in "The Sound of her Voice". Starship abilities hinge on what the story of the moment demands.