Carronade technology is around half as expensive so you can advance up their technology tree MUCH faster, usually about two sometimes three technology levels higher then the equivalent other weapon systems. Carronades also effect ground troop weapon strength if not having two or three levels better ground troop weapons strength is a huge advantage I don't know what is.
Yeah, but I'd argue that's a bad thing. The ground combat system wasn't designed for being able to artificially inflate your attack so far above armor at a given tech level and doing so is basically mandatory against another player. It's only so cheap in an effort to balance it against other ship weapons. It might as well be renamed to Ground Attack Strength and moved into the Ground Combat section.
As Carronades is far cheaper and fire much less often they also consume way less MSP in prolonged combat engagements and also is cheaper in general to fit into your ships which can be important in many regards.
This is interesting and I hadn't considered that aspect.
I think that Carronades is in a very good place at the moment and serves a very interesting role...
We're going to have to disagree on that one. They're very attractive as a ground weapon but the only situation I can see in space where a full load of carronades is better than equivalent tech cost lasers is maybe if your enemy is dumb enough to standard transit through a jump point and land within 20k of you.
60 cm C8 Plasma Carronade (1) Range 192,000km TS: 3,000 km/s Power 96-8 RM 10,000 km ROF 60 96 48 32 24 19 16 13 12 10 9
35 cm C8 X-Ray Laser (1) Range 192,000km TS: 3,000 km/s Power 32-8 RM 70,000 km ROF 20 32 32 32 32 32 32 32 27 24 22
Beyond 30k the laser does more damage, fires three times as fast and is 58% the size of the Carronade. It's debatable whether the Carronade wins even at 10k as both a 96 damage PC and a 32-damage laser penetrate 9 layers of armor, the laser will fire 3 times for every Carronade shot, and you can fit a lot more of them in the same space.
Making Carronades smaller won't make them much more useful at long ranges but it would make them more competitive against equal tech lasers in their supposed niche.
EDIT: At very low-tech levels the ability to research very large carronades so cheaply does make them more competitive at range see:
30 cm C3 Plasma Carronade (1) Range 192,000km TS: 3,000 km/s Power 24-3 RM 10,000 km ROF 40 24 12 8 6 4 4 3 3 2 2
15 cm C3 Near Ultraviolet Laser (1) Range 180,000km TS: 3,000 km/s Power 6-3 RM 30,000 km ROF 10 6 6 6 4 3 3 2 2 2 1
At this level, the carronade's damage actually falls off slower than the laser because of the comparatively low laser range tech. Still, the laser is 55% the size, fires four times as fast, doing the same damage over time even at 10k and both weapons have 4 armor penetration at point blank range. I suppose the carronades do quite a bit more shock damage though. I don't know how to evaluate that.
EDIT2 TLDR: I don't actually think early Carronades should be able to out range lasers at the same tech level or be usable to game the ground combat system or only be viable as low-tech weapons. I'd like to see them rebalanced to be viable in their niche for the whole game without conveying early game advantages. Making them smaller alone won't accomplish this, it would probably require some kind of very very expensive range boosting tech to make them more useful in the midgame while reducing their range early.