Why would a huge space station fire micro torpedoes? That sounds ridiculous. I always assumed they were the same "Spock coffins" as the rest of Trek.
Because those turrets are not big enough to host full launchers. The lauchers on the Galaxy are 20-40 meters long. Perhaps the choice was between putting an inferior "glued on" short range, slow rate of fire full size launchers (like on a runabout) or putting micro torpedo ones that have high rate of fire in order to repel amassed enemy ships.
I'll look into it when I get a chance.
I do agree that it's a bit ridiculous. They shoud have installed full launchers all around the outside docking ring and pylons instead of bothering with rotating turrets.
But the torpedo launchers on the NX-01 Enterprise were only a couple of meters long and the TOS 1701 ones were probably smaller (the entire lowest saucer deck being the size of the bridge - which is probably the same size as the rotating launchers on DS9)
Just because the 1701-D gives the impression of a long launch tube, doesn't mean thats the only way they can work.