That's incorrect. Naval cannon shells fire on ballistic trajectories determined by the range of the target and the firing angle of the weapon. Effective firing range depends on many things, and in the case of battleships the guns may be MORE effective at long range with a higher firing angle where the shells have to "drop" through the thinner deck armor of the ship. OTOH, those same cannons are somewhat less effective (although more accurate) at short range, where the trajectory of the shells is too flat to get through the deck armor and they have to contend with the thicker belt armor of the ship (or pound the ship's superstructure, which will wreck it but will not sink it).From a usage standpoint, guns fire directly on target and torpedoes can be either direct or indirect (track to target).
In space, kinetic kill vehicles (which may or may not be ordinary cannon shells) gain their killing power by high relative velocity on striking the target. This means that the faster you are moving relative to your target, the more damage you are going to do when you hit him. Nuclear weapons have no such advantage, but can be delivered the same way: one starship accelerates to high speed, drops a nuke behind it and detonates it just as they pass.
Directed energy weapons travel at or close to the speed of light and ALWAYS on a flat trajectory; you do not have to lead your target and it doesn't really matter what range your at as long as you have an accurate firing solution. Directed energy weapons are more effective with sustained contact at a single point of the target and thus require extremely accurate firing solutions to be effective, and this is even more true in the presence of shielding. Therefore, directed energy weapons require you to very precisely match velocities with the target vessel and maintain a very accurate target lock on the part of his ship you want to hit.
IOW: Kinetic kill vehicles and nuclear weapons would usually require you to fly towards your target as fast as you possible can, fire off a few shots (nukes and penetrators together) and then count your hits as you zip by each other at some insane relativistic velocities. Directed energy weapons, on the other hand, are most effective when you match velocities with the other guy so you're almost stationary with him and try to drill through his shielding with energy beams or smash him to bits with a (relatively slow moving) torpedo. Those are two ENTIRELY different kinds of combat; it's similar to the difference between a sword fight and a jousting match.
Except photonic torpedoes can do this consistently WITHOUT accidentally blowing up the ship that fires them.In "Silent Enemy" Enterprise's phase cannons "blew up the something the size of Mount McKinley." They're not that much weaker than a "photonic torpedo" which supposedly can put a "3km crater in an asteroid" at full yield.

The torpedoes were not. And it was the torpedoes -- NOT the phasers -- that Kruge should have been worried about.The phasers were still back there.
Kruge WASN'T above. He was behind when he decloaked and he was behind when he fired.Kruge could've easily fired on Grissom from above
Neither of which would have caused as much damage as quickly as a pair of photon torpedoes right in the grill.Hypothetically, as fast the writers would need it. Although they could've just fired aft phasers instead. Or raised shields.
Except that it usually ISN'T, and dialog suggests there are technical challenges for doing so (otherwise Spock is wasting everyone's time by ordering for multiple phasers to be fired on the same target).Sure it is. Your own examples point to more emitters being added as each ship gets bigger but the preference is still to use 1 or 2 emitters at a time regardless of how many emitters are available. The extra emitters appear more for firing arc coverage but not as additional firepower since the ship's power can be fired through 1 or 2 emitters all at once.
Defiants aft phasers are weaker than its forward phasers.Yet you haven't shown any evidence that one weapon is weaker than the other on the same ship.
The Bird of Prey's aft distruptors are weaker than its forward disruptors.
The Enterprise-A's aft torpedo launcher is weaker than its forward torpedo launchers.
The Vorcha's aft disruptor cannon is weaker than its forward disruptor cannon.
Arguably, the Romulan Warbird's forward disruptor cannon is far stronger than its (probably non-existent) aft cannon.
Indeed: NX-01's two forward phase cannons are stronger than its solitary aft phase cannon.
For all of these ships, the relative strength of their weapons has no determination at all in attack direction, EXCEPT that sometimes enemies will attack where the weapons are strongest with the express intention of taking those weapons offline (as Duras does in "The Expanse").
2 torpedoes+ 12 phaser emitters are stronger than 0 torpedoes +2 phaser banks. And Yet in the TOS movies we have three Klingon commanders whose very first attack is from the FRONT, where all of those weapons can be brought to bear against them.Which weapon is demonstrably stronger than the other?
Was it? We're told the aft shields are down, not that they've been hit. Hitting the ship in one of its shield generators would accomplish that instantly; hitting the shield barrier itself probably wouldn't.The first point we're shown from the exterior is of the BOP already attacking the Bortas from the 2 o'clock position. The 1st hit offscreen scored the aft shields...
You're asking me to prove a negative? YOU'RE the one claiming that they can and should be able to determine that. I'm deducing that they can't from the obvious fact that they DON'T.That's your assumption that it can't be determined, but where is the evidence?
Where's your evidence, therefore, that they CAN?
How the hell can they know that? YOU didn't even know that until you built a 3D model and tried to project its blind spots and you didn't even do it correctly. You think the tactical officer has time to sit there drawing models on his computer console to figure out where his main phasers can't fire back?If enemy ships as early as ENT can target weapons then they can see the weapons and know where they can shoot
And when has anyone ever scanned for the enemy's LINE OF SIGHT? Something like "Can he see us from outside of that particular window?" or "We've knocked out their forward cannons... can they still hit us with their aft cannon?"Even the NX-01 can scan enemy ships for weapons, shields and propulsion capability.
Anything remotely similar will do. Again, it is YOUR suggestion that being able to determine weapons location means it should be easy to calculate their firing angles and also the potential gaps in those angles. Has anyone ever ACTUALLY done this?
Where's your evidence that it CAN?so where is this evidence of yours that says that combatants aren't aware of the weapons arcs again?
Yeah great... so where's the part where Reed says "By the way, their forward plasma cannons are limited to thirty degrees yaw, fifty degrees positive and negative elevation"? I don't see it in the transcript. Maybe it's in a deleted scene?"Fortunate Son"
ARCHER: We've scanned your ships. Mister Reed.
REED: Fore and aft plasma cannons. I doubt those shields of theirs would hold up to our torpedoes.
Hm... I just watched that episode, but Data never mentions that the desroyer's disruptor cannons have full omnidirectional coverage. Another deleted scene, perhaps?"Conundrum"
PICARD: I'm aware of that, Commander. Tactical analysis, Mister Data.
DATA: The destroyer has minimal shields. Their disruptor capacity appears to be only two point one megajoules.
I don't have the Blu-Ray version so clearly I don't have the deleted scene where Worf goes on to say "However, analysis suggests only three to five of those disruptors can be brought to bear on any particular target.""Nemesis"
PICARD: Tactical analysis, Mister Worf.
WORF: Fifty-two disruptor banks, twenty-seven photon torpedo bays, primary and secondary shields.
You've made the positive assertion that tactical analysis includes a detailed examination of the firing arcs of those individual weapons. Do you have PROOF of this or is this something you just made up and are now asking me to disprove?