Well, I played my previous campaign almost without missiles and the current one without any missiles at all due to this annoying bug that erases your gallicite stockpiles once you try to build them. Sometimes even when you think about them.
Given that obviously I couldn't miss this thread.
Well, first thing needing to be told is that missiles don't really provide as much tactical depth as you would think. Sure, missile designs themselves maybe (though even without them ship and fleet design is already deep enough), but in an actual battle they're rather meh - both sides can reliably defend themselves from them with enough gauss spam and you just keep launching them until one side dies. They have a bit more logistics overhead, but that's rather outside of the battles themselves, though.
Beam firefights have a great potential to be equally boring, BUT if you're lucky to get a very similar speed to the npr and tech level equal or a bit lower than them, things really start to get interesting, all the ranges, crazy manoeuvres coming from nprs splitting their fleets randomly and flying in different directions, suddenly making you either too close or too far to them... I was lucky enough to hit that sweet spot of balance in my very first try and my first campaign revolved around these exciting battles a lot.
As for the actual weapons I dare to disagree with comments above. Firstly, lasers
aren't an all-round weapon like players tend to depict them. They have great damage potential, but only from a very close distance. From my observations the damage falloff is brutal (yes I am aware of wavelength tech, still falloff remains brutal) and particle beams of similar tech will outdamage lasers at their max range since they deal same damage at all ranges. Technically for kiting at max range lasers are better if you're faster because you'll get more range out of them, just enough to outrange particles, but you'll deal only 1 point of damage in such situation and most your shots will be misses, so make sure to have plenty guns and msp to feed them through this loooooong engangement. And adding a shield, even a very weak one desgined specifically to nullify these sporadic 1 dmg hits and nothing more will allow you to comfortably sit at particle beam ranges and blow up enemy after enemy which dared to use the above tactics without caring about their lasers (ecm advantage works here too). Unless they're faster. But speed is always most important. Even for missile fleets, because you want to be able to maintain range or get away or chase enemies down no matter what you use to kill them. So faster speed for staying on top, but only a very slight difference between your opponent to get the max fun out of battles.
As a last note, gauss aren't as useless as you might think. Had many ships destroyed that way, feared lasers better than mine, got too comfortable (and too close to finally get a meaningful laser damage) and lost many ships thanks to the gauss volleys alone. The thing is, you can cheaply stack these turrets and just destroy stuff through the sheer amount of hits, even if it's only 1 dmg each, so I can see some heavy armored gauss squadron work. Though probably railguns would be better at this role, I think. Probably. Never underestimate hundreds of 1 dmg hits every damn 5s like I once did.
Last but not least, you've mentioned splitting fleet yourself. Highly impractical in most situations, but damn it does produce cool battle screenshots. Bonus points if different ships have slightly different speeds like in my first campaign. Some were tiny bit slower, some tiny bit faster than enemies and I had three different speeds in total, so naturally I'd be splitting them and whatnot. Fun times they were. Missiles did spice things up here and there a few times, but their fun value for me was just some more variety on the battle
fieldspace, on their own they are nowhere near as fun to use in battles themselves as beams.