I think the missile role is pretty indisputable. Range, power, locking, slow heavy hits, possible to shoot down.So I guess low damage just makes cannon shots look like needles at the moment? The pirate station cannons and my X-wing cannon shots are all needle-like. I should test what wider configurations look like.
Also, I was able to test the doom beam a bit (same testbed setup, but half the beams as a slave) and it seems balanced other than range. Beams right now are way too low range (1600m), you pretty much need to be nuzzling your target to do damage with default sector size. And good luck hitting a moving target from more than 1600m away with missiles or cannons with how laggy things get and how erratic movement can be as a result.
This gets into what the roles for each weapon should be. Overall, I feel the role setup should be very Star Trek-like because Star Trek battles look absolutely beautiful without being overly complicated (tons of beams, missiles to finish things off, some small ships using cannons instead), but of course Trek isn't very deep and doesn't quite have the weapon variety (mostly PD is missing and cannons are too niche), so I think a little inspiration should come from Sword of the Stars, which has incredible weapon variety and good balance, and a few other places of course.
So, here's my thoughts on weapon roles in B, C, M order:
So, as to how ranges should work with all of this, I think everything should just stop after so many sectors, but things should have different effective ranges due to accuracy and travel time. You wouldn't want to use cannons from 2km away unless your target was gigantic, and you would want to use lock-on missiles and sniper cannons for targets that are a bit too far to accurately target your beams onto.
- Beam: Your go-to weapon for small-medium ships at medium ranges, does more damage to shields. Most ships should have this.
- Beam-beam: The Enterprise's doom phaser from All Good Things, charges up and just plain punches a hole in a Vor'cha with one shot, but it only fires forward. And weakens your shields I guess (Stargate had this a little with the Ori ship beams, but all of these weaknesses together I don't think any one thing had, and it's possible that the current setup is too weak in actual PvP).
- Beam-cannon: The faster-firing phaser setup of some ships like the TOS enterprise, good mainly for assuring hits on smaller ships or taking out little turrets one by one. Also good for Zahn Consortium-style PD (from Star Wars: Empire at War's expansion, little blue lasers of awesomeness to stop incoming missiles).
- Beam-missile: This is the hardest one to find a role for. Perhaps this can be a disruptor and they're better for taking out systems than hull.
- Cannon: Higher rate of fire but lower accuracy/range than beam, good for small ships to take on larger ships at close ranges (like the Klingon Bird of Prey or Defiant vs. a big battleship).
- Cannon-beam: Sniper cannon, basically the complete inverse of a cannon (long range, high accuracy, lower rate of fire); still good for small ships though as they can dodge at range. Pretty much only SotS has these, and they work rather well; I don't think these should need charging, just a longer reload.
- Cannon-cannon: Rapid fire cannon, veering more into Star Wars territory really, but with the current default cannon fire rate, you need this to an extent to get proper Defiant/BoP setups.
- Cannon-missile: Either cannon version of the disruptor beam (but you won't get the fire rate needed for a BoP...) or, to go a bit out-there, BSG-style flak guns, so as to be cool PD and not redundant.
- Missile: Very high hull damage, low rate of fire
- Missile-beam: Proper photon/quantum/plasma torpedos (lock-on, high damage but a bit slow), better hope your cloak is working or your unshielded BoP is history.
- Missile-cannon: SotS dumbfire racks (maybe it can only use .25 or some other fraction of a missile per shot?), intended to overwhelm/distract PD at close range with a flurry of fast missiles.
- Missile-missile: Star Wars style bombs, so fighters aren't just those lousy Peregrines that didn't matter in the Dominion war.
Beams vs cannon - I am drawing from games like SoTS, Distant Worlds, Stellaris, Galactic Civilizations, MOO series, and more. Weaponized beams travel at the speed of light, but because they need to be focused at their target's distance for maximum effectiveness they can't just go on forever and actually do anything more useful than being a very bright flashlight. Projectiles are less affected by range and things like space dust that could reduce the value of a beam weapon over distances.
The combination of near-instant effect and digital-level accuracy has always struck me as ideal for point defense, where targets move at extremely high-velocity (missiles should be moving several times faster than any ship). That and issues of dust and focus have always left me thinking that beams are the best possible solution to outputting insane damage at short range and handling point defense.
Theoretically projectiles would be almost as good at long range as missiles, but their substantially sub-light speed level ruins that unless the target's future acceleration is known 100% - after a certain range you just aren't going to hit with them. They are fast enough to be extremely effective mid-range though, and don't require the same amount of space as missiles. We also know that IRL they can be fired en masse at very fast speeds, which compensates a little for their accuracy falloff at range. They're also effective at short range, but not as fast or accurate as beams for intercepting very fast targets, and probably not able to deliver the same kind of power as an intense, focused particle stream.
It's all sci-fi though. We can speculate about science in fictional scenarios all day to no avail. Honestly it doesn't matter much to gameplay if they tier range by weapon family, or by slave.