(1: what if the saucer separated? The secondary hull would need its own phasers and torpedo launchers, both fore and aft, as would the saucer
Probably not, as the secondary hull would be space junk instead of a spacecraft. The TOS or TMP ships were never indicated as being capable of operating after parts of them were jettisoned, with the exception of the saucer section (mentioned in "The Apple").
(3: the flagship Connies would have to have at least as many torpedo tubes in the TMP era, since TWOK established that Reliant obviously had at least four tubes, two fore and two aft.
What flagships? For all we know,
Constitutions were among the lesser ships in Starfleet arsenal.
OTOH, in recent history, the biggest and baddest ships had considerably fewer torpedo tubes than the humblest and most vulnerable. Very few battleships carried any torpedoes at all, whereas a tiny destroyer might well pack up to sixteen tubes. Perhaps the
Constitutions indeed were Starfleet's top vessels, which meant they didn't have to stoop to carrying weakling secondary weapons such as torpedoes, at least not more than the number of tubes needed for the occasional planetary bombardment, probe launch or tactically surprising spread.
(4: It would be unwise for the Connie in any era to have all of its weapons concentrated in one part of the ship with no redundancy
It doesn't seem as if starships in TOS can afford much redundancy: there always appears to be just a single powerplant, for example.
OTOH, concentrating one's assets might make it easier for one to protect them. Many old warships were built on that all-or-nothing principle.
Exactly. The TOS/TMP Enterprise at warp (or running with warp at sublight speeds) isn't limited to traveling in the direction that she's pointed at.
We might have an onscreen confirmation of sorts for that in "Balance of Terror" where Kirk apparently retreats from the plasma weapon by warping backwards. Or at least neither the original or retooled VFX indicates that Sulu would have turned the ship around - the starfield effect on the monitor would probably have reflected that, at least initially, until Sulu had time to reset the cameras to lock to the incoming weapon (and thus point directly aft).
If the ship can reverse at full warp, it sounds pretty likely that she can move in any orientation at full warp. Although of course it might be that only movement along the axis of the nacelles is allowed. But then again, Kirk told Sulu to pivot at warp in "Elaan of Troyius". And the opening credits have the ship warping at what looks like a nose-down orientation...
Again, you don't refer to individual torpedo projectiles when firing, only the launcher.
But the quoted dialogue would indicate otherwise. That is, when you refer to the launcher in the real (if bygone) world, you apparently may indeed use the word "torpedo" rather than "tube", despite the fact that you actually refer to the tube. Which would nicely cover the two times "torpedo numbers" were used in TOS, allowing us to interpret them as tube numbers instead.
One forward launcher in the saucer, right above the captain's yacht.
And only ever seen firing quantum torpedoes at sublight. Might be a dedicated launcher for doing that, because none of the other tubes on that ship ever fired quantums.
For Nemesis, they added another tube right above the aft shuttlebay, and two more behind the bridge.
And apparently also one tube on saucer bow, and one on dorsal superstructure bow.
At least the shuttlebay tube might well "have been there from the beginning", though, since we never saw that part of the ship up close in sufficient detail (indeed, the flashing of a running light obscured the area in ST:FC shots).
This latter installation seems pretty stupid, as there's no way to really provide for a reloading mechanism since they're located above the docking bay.
Might be a defensive turret installed when it became obvious that those small Dominion "battlebug" attack ships didn't yield to standard phasers... A desperation move rather than a well-integrated weapons system.
Timo Saloniemi