The point of box launchers is to overwhelm point defense with a massive volley size. That's a strictly tactical purpose, however it is extremely effective, and as a consequence of that effectiveness the strategic problems caused by using box launchers (lack of magazine depth + need to transport and reload ordnance) are greatly outweighed by the strategic gains from the tactical efficiency - you destroyed several ships or even an entire enemy fleet with no losses aside from the expended ammunition.
This sounds good on paper, but in my experience it is overly reductionist.
My last two games I've been using carrier strike groups as my main fleet doctrine; in the current game I'm fielding 50,000 ton carriers that can deliver sixty 250 ton fighters with four size-4 box launchers apiece, generating a maximum salvo size of 240 missiles apiece, with two reloads in the carrier's magazine. So I have been unleashing some very big box launcher salvos myself.
I have, however, encountered hostiles which are fairly resilient against even this titanic salvo weight.
The first issue I've had is one of targeting. Even after first battle contact is made, the enemy will occasionally produce a new class of ship I haven't seen before, and I'm forced to guess as to its role. Jumpship? Beam ship? Gauss? AMM? Missile ship? Despite handily saturating their point defenses with my salvos, I've found that I simply don't have enough ammo to comprehensively destroy (or even render hours-de-combat via distributed damage and/or overall effective losses inflicted) ships with engine tech a tier below mine. This forces me to choose my targets, and when some of them are unknown I can neither properly prioritize threats to let my beam ships mop up the remainder nor be sure that I am allocating sufficient, but not overkill numbers of missiles to each, since I don't know what their passive defenses (shields + armor) are like. Furthermore, RNG will have its say; both in which salvos are degraded and which ships manage to survive X number of missiles via having the hits spread across their armor instead of stacking up in one spot and/or rolls for internal damage. Those ships require follow-on strikes; which in turn impacts my targeting decisions - it is most optimal to destroy their PD ships (especially AMM ships given their dual threat) with the first deck-load salvo so the next two are more efficient.
In theory, if I disposed with the carrier and the majority of my beam fleet entirely and went with just box launchers and PD, I suppose it's possible to achieve the on-paper "perfect salvo" in which every missile is expended at once (so the "cost" of overwhelming PD; i.e. the maximum number of missiles the PD system destroys on average, is only paid once,) and such sufficient over-match of assigned damage is achieved (50% or whatnot) that there is no chance of imperfect targeting borne of imperfect intel allowing any survivors (assuming that you don't target large tonnages with commercial engine signatures.) Since none of this is relevant to NPRs as-is, I won't say "but that's a boring way to play" and instead observe the tactical and strategic limitations - if they produce another fleet from somewhere else, and you have expended most or all of your munitions, I am in trouble. Even if I have reloads along, I'll have to stay stationary for a significant length of time to reload box launchers from a tender. Its flexibility is further limited by the need to conduct jump point assaults - box launchers tend to explode a lot more than magazines and larger beam weapons are fairly efficient at producing shock damage which might encourage such things.
Then there's the alternate case where I
do have decent intel on the target and know which ships are the PD ships. If I can reasonably expect to bring enough reduced-size launchers to any roughly equal-tonnage scrap to comfortably overwhelm the defenses of the enemy's doctrinaire % of fleet tonnage devoted to PD and achieve a minimum amount of damage (resulting in effective degradation of the hostiles overall PD capability) then at some point it becomes more efficient to use multiple salvos fired from reduced-size launchers; as once the PD ships are dead, the remainder are more or less helpless. Even a beam fleet turning its main guns loose can only blunt, not stop, a serious salvo; without a significant tonnage of massed 10cm railguns they're not going to shift the needle too much. And 2/3 beam fleets will be using lasers or particle beams!
To be clear with all this, I'm not indicating doubt as to how the Perfectly Optimized Meta Fleet Matchups shakes out in terms of most efficient weapons system, but expressing real doubt that box launchers are truly dominant in an actual practical sense, in campaigns, with a theoretical human opponent playing a second empire to stand in for The Theoretical Perfect NPR AI. Other dangerous doctrine mismatches (which could be added to NPRs for balance or already exist as spoiler threats) include inverting the saturation threat - coming after box-launcher centric fleets with hordes of box launcher torpedo bombers - or for that matter, big balls of railgun fighters (with some laser/meson fighters mixed in to help punch holes in ship armor once they get close.) This is a matter of saturating the available fire controls on the box launcher ships. Yet another tactic could be large ships with commercial engines that turn out to be warships, to weaponize the targeting problem - combined with large hangars and they could also prove flexible enough to keep some surprise advantage after initial contact, as well.
I'm not advocating for any of this as suitable for NPR AI; I'm just trying to illustrate that getting down to the "real" (im)balances present in the game's rules as-written requires fully considering the strategic implications, and that those are so innately linked to the NPR's decision-making ability that our choice of comparative baseline in that matter could well result in situations where even a significant tactical advantage could be rendered moot. (This is in part due to the inherent one-trick-pony problem that any strongly biased fleet design doctrine will have, of course.) It's convenient to use terms like "roughly equal tonnage" when comparing things, but even that doesn't account for production effort invested into filling magazines or hangars (or god forbid, both!)
To get down to numbers which can start to give us a roughly objective picture to compare to our necessarily subjective experiences playing campaign games is a daunting task and will involve adding up a lot of mineral costs. It's a complex enough issue that we may have to write an entire simulation program just... to...
.... wait. I believe we HAVE one!
... now I just need to find the time to use it in that fashion. And perhaps a set of generic empire starting parameters to use...
Ultimately, the complaint about AMM spam is the same as complaint about NPR home world ground forces - they are 'special' cases that break the usual rhythm of the game. From a gamist-POV, your fleet that just wrecked the NPR fleet and your army that already took over their mining colonies SHOULD be able to defeat their final defenders and then subjugate their home world without you having to change your playstyle. Except that's only because you're a gamer, playing a game, and approaching the situation from a game developer / scenario designer viewpoint.
This is precisely why the mechanical questions are important - the answers will illustrate whether AMM spam only
feels like a special case due to contrast with the limitations of NPR fleet/ship design doctrine as they now stand, or if they are inherent to the mechanics and will always manifest at a level that over-rides even large outside influences like strategic production, operational flexibility, and significant fleet doctrine mismatches.
If it is the former, it means that AMMs are exactly what they
should be given the general thrust of the overall game rules; all-round weapons who's flexibility comes at the cost of tonnage efficiency against warships. Frankly, the RP considerations take care of themselves from there. When contemplating the tension between game rules and RP, it's worth remembering that real-life naval combat theorists, tasked with the same challenge Aurora players have (making irrevocable decisions years in advance that will determine the fighting abilities of entire national fleets for decades to come) built mathematical tabletop wargame models very much like Starfire and intensively gamed out various scenarios. These games took into consideration both statistical lessons and real-world strategic limits (in larger wargames, the staff officers of various ships would isolate themselves in separate rooms and runners would deliver messages on slips of paper to simulate orders being given by radio, for instance; so even the human element of staff teamwork and efficiency was considered.) This produced the theory of more, smaller guns being able to defeat fewer larger guns by steady degradation of the hostile's fighting efficiency without penetrating a main armor belt. This theory was put into practice at the River Plate, and proved successful - though some crewmen on the three British cruisers who's ships caught some massive 11 inch AP rounds viewed the results as less clear-cut.
In short, when dealing with mathematical models of simulated reality, the numbers
always matter; but
how and
why depend entirely on what your
goal is. If your goal is the existential survival of your nation-state, then you will never, ever stop tweaking. If your goal is to produce a reasonably consistent and plausible simulation of Space Empires Going Pew Pew In Space, then sufficiently ovoid cows will be good enough. You still want as good a grasp on The Numbers as possible to make life easier, but you'll pass the threshold of "perfectly fit for purpose and practically perfect" within a human lifetime, which is a good thing.