In short:
Current Mesons seem to me to be like the worst weapon compared to everything else.
In long:
In my current doctrine, I use Particle Beams and Mesons Cannons. I’ve been trying to figure out what Mesons would be better at than other weapons, and so far I haven’t found an answer.
(Spoiler: Raiders)
In my battles with the Raiders, I used 9 T4 20cm (20% AR) Mesons with a 10-second reload time on a 37kt cruiser. Enemy had only 2 layers of armor. Weapon range was 250k km, DFC range 320k, the difference in speed was ~2k km/s in favor of the Raider.
Maybe I was too unlucky, but the number of hits on the internal systems did not exceed about 60% of all hits. On average, these are 2-5 hits on internal systems. Sometimes my ship was so unlucky that the enemy approached almost point-blank (~50k km), and only then did the engines get damaged.
What I’m saying is… Mesons do very little damage on their own, and unless you’ve researched a bunch of technology and if you’re very unlucky, even paper will stop half of your projectiles.
At the same time, Mesons are very poorly combined with other weapons. The rest of the weapons either cannot help them in destroying the enemy (against shields), or they work much better than them (against armor and HTK). By comparison, HPM works well with Plasma and Railguns, as they can quickly strip a ship of its shields - and the enemy will immediately be blinded.
I know that Mesons are not designed to destroy a ship on their own, just like HPM, but HPM has a much more tangible effect. If you hit with 5 T1 Mesons once, the enemy won’t even feel it. If you hit with 5 T1 HPM once, the enemy will not be able to shoot. As support tool, HPM feel much more useful than Mesons.
If we talk about shields, they only really become a problem when you’re fighting 120kt ships or 70kt stations. But the problem for Mesons is that such opponents almost never have 1-layer armor, and they have hundreds of HTK. 1 damage shots on such ships look a little hopeless.
Meson shots ignore shields, and they are probably the only real reason to install armor instead of additional shields. However, if the ship has a good repair capability, the only threat from the Mesons would be an accidental reactor/engine/magazine explosion.
In general, I don’t like Mesons. They are not reliable - they can weaken or destroy an opponent with the first shot, or they may not cause significant damage to him during the entire battle. Instead of using some kind of high-caliber laser with rapid-fire plasma, you need to hope that your shots will go through the armor and break some important component. There is a possibility of instakilling an entire dreadnought by simply hitting the reactor, but this possibility is negligible. I think they were a much more significant threat back in the days when the Mesons ignored armor.
However, I would be interested in how my ships would perform against the Mesons.
I don’t want to say that it’s a terrible weapon and needs to be rebalanced, rather I want to understand what I’m doing wrong.