Another consideration this article doesn't seem to touch on: Heat.

Particle-beam weapons especially, but also anything carried by a ship that generates significant energy that isn't thrust, is going to generate a lot of waste heat, due to those blasted laws of thermodynamics. Where does all that heat go?

Yes, space is very, very, cold. But vacuum is about as close as you can get to an ideal thermal insulator, so if you want your imaginary warship to be spamming giant lasers like a Gradius boss, you're going to need some way to rapidly dispose of heat before your entire ship cooks like a P4 with no heat sink.