Well you can add more fake/non-destroyable hardpoints to a ship. You just duplicate the hardpoint on the capital ship you want to add more firepower to (you're just reusing the existing hardpoints for the model), give it a new name, make sure to set the extra hardpoint as non-targetable & non-destroyable, adjust the weapon data as needed, and add the new hardpoints to the hardpoint list of the ship. Ships/stations can put a much larger volume of fire out using this method. There isn't an upper limit I'm aware of using this method, but it will affect the performance of the game with all the additional lasers/missiles/torpedos flying around on screen. Doing this requires you to tweak the other value settings for the ships and stations if you don't want everything on screen dying even faster than normal though. I personally increased ships/stations hull & hardpoint health and shield values to make my battles last longer while enjoying the additional fireworks. At least one of the existing available realism mods already uses this method. I don't remember which one though as I've downloaded and merged together parts of several mods for my own personal use.
I have started experimenting with the permanent planetary bonuses assigned in PLANETS.XML. It is possible to assign these other bonuses (look in UPGRADEOBJECTS.XML) to specific planets. You can even assign more than one permanent bonus to any given planet if you wish.