Arc emitters suck, montu did a test proving they’re the worst XL weapon
There are at least a couple of issues with that test: the other weapons included don't synergize at all with the FAE, and the defenses chosen are slanted against penetrators/for anti-Hull (which TL/NL/GC/KA all are to some extent).
The standard Tier-0 kinetic weapon is the Mass Driver, which goes up to Gauss Cannon at Tier-4, and includes S-, M-, and L-slot variants - same deal on the energy side with Red Lasers going up to Gamma Lasers. They each have a favored defense (Shield for GC, Armor for GL) against which they do an additional 50% damage (i.e., takes 2/3rds as long to get through) and a dreaded defense (Armor for GC, Shield for GL) where they do 50% less damage (i.e., take twice as long).
When these tech trees reach Tier-3, they can also veer off into advanced weapons - Kinetic Launchers (KB, KA) or Particle Launchers (PL, NL) - at basically a Tier-3+ tech (12K tech points over the basic Tier-3 tech). Immediately, there is both the typical plus-Tier increase in base damage (30% over previous) and then a bunch of additional bonuses. Kinetic Launchers jump their vs.Shield damage to 200% (i.e., additional 25% faster than GC), bump up their vs.Hull damage to 125% (i.e., 20% faster than GC), add 20 points of Range, and have a longer Cooldown (i.e., do their damage in bigger chunks, possibly getting a target to 0 Hull without giving a Disengage chance). They do all that at the cost of a top-end Tier-3 tech, more Power needed to run them, and a 5% hit to Tracking. Particle Launchers are IMO far worse, with a straight 75% bump to vs.Hull damage (i.e., only takes them 53% as long to get through Hull), a FIFTY-point jump in Range, and well over a tripling of Cooldown (i.e., now massive chunks of damage), and again just one tech, some Power, and a blip of Tracking.
X-slot weapons get an even bigger advantage than the advanced L-slot weapons above, mostly to try to get Battleships back to 6x the damage output of a Destroyer (equal to the damage advantage of an L-slot over an S-slot). For a Mega Cannon, it's a size above an L-slot GC, so you'd expect a 2.45x (square root of 6) for a simple size increase, but instead it's 2.88x the damage. Like the advanced weapons above, there are vs.defense differences, with a scale-back on vs.Armor to only a 25% hit (i.e., 25% faster than GC) and the same 25% bump to vs.Hull as Kinetic Launchers (overall it makes them more balanced, though less useful as a platoon specialist alongside a vs.Armor weapon). It also makes a big jump in Range from 100 to 150, and over a 160% jump in Cooldown - all this at a cost of a 20K Tier-4 tech (vs. 12K Tier-3 for KB), over 3x the Power (vs. 2x for the size increase), the same 5% Tracking hit as above, and a forward-fire limited-arc restriction (which may not actually be all that meaningful). The Particle Lance has a similar profile versus the GL, with 3.02x base damage, now 200% damage vs.Armor (i.e., 25% faster) and 150% vs.Hull (i.e., 33% faster), Range jumping from 80 to 150, and interestingly only a 74% increase in Cooldown (vs. almost 250% for PL),
(Edit: originally had 250 for Range for both Cannons and Lances - where TF did I get that? Sorry...)
On top of those increases, you jump up to the Tier-4+ versions of the X-slots and the advanced L-slots, adding in another 30% damage each. So how do the penetrating weapons compare.
Right off the bat you're hit by three problems that basically eliminate any comparison between KB/KA, PL/NL, and penetrators:
- The only Tier-4 penetrators (Disruptors) are just available in S- and M-slots.
- The only L-slot penetrator (Cloud Lightning) is both a salvage tech and a Tier-2 (and actually not involved in researching the X-slot penetrators).
- There are no Tier-3+ and Tier-4+ L-slot advanced weapons that are penetrators.
Then we add in the Arc Emitters, which as X-slots over a theoretical L-slot Tier-4 Disruptor, should have similar size and other advantages over their more ordinary (specialized vs. the more basic Gamma Lasers). The theoretical L-slot Phased Disruptor would be the same costs and Power as an L-slot GL, with 93.1 average damage per hit, and 15.26 average per day, compared to 80.30 per day for the Arc Emitter (5.26x!). The AE only gets a 33% increase in Cooldown (though mitigated by the bonkers base damage increase) and there are no differences in versus-defense damage (again, base damage increase mitigates).
(Edit: again with the 250 Range, sheesh...)
If you simply compare the three X-slot weapons and their damage rates against their weakest versus-defense rates, the FAE holds up relatively well, taking 66.3 days on average to get through six Crystal-Infused Plating (660 each) on top of the base 3000 Hull, compared to 64.2 days for a Giga Cannon to get through six Neutronium Armor (870 each) and the Hull, or 83.6 days for Tachyon Lance against six Hyper Shields and Hull. They also fall off predictably once Improved/Advanced Battleship Hulls are added in, and more so once Crystal-Forged Plating is swapped in (even with Dragonscale Armor added as well, Giga Cannons still rein supreme at 86.1 days, but Dark Matter Deflectors bother Tachyon Lances enough to still take longer (110.2 days) from first shot than the FAE (107.2 days)). With all three defensive layers at even, un-repeated levels (2 L-slots each) plus both Imp & Adv Hulls , the three weapons each cut through the defense in basically the same amount of time from first shot (FAE 65.0 days, Tach 67.9 days, Giga 67.9 days) when used on their own.
I don't think Arc Emitters have to be as bad as they are currently. They need:
- Pairing options that synergize better, i.e., other penetrators that are comparable to other Tier-4+ advanced weapons.
- Those other penetrators have got to not suck on their own, so that the jump to X-slots isn't so odd.
(Edit: and the last 250 Range is gone now.)
I'm not sure right now what it would take to make that work, but I think leaving it at "they suck, so why bother?" is a bit shortsighted.