There's something that I feel alot of space-survival/construction games miss out on, weapon customization. Being able to design/tweak weapons and ammunition adds a layer of depth to combat. Instead of everyone using the same turrets people could design their weapons to work well in certain situations. Plus it creates an occupation for more engineering-minded players. Look at From The Depths as an example of weapon customization done right. A similar (But simpler) system would definitely add variety to combat between ships. Having in-depth weapon customization would create more opportunities for advanced players to use their knowledge. This also adds another level of constuction because now players could create weapon companies to sell their weapons or blueprints. Of course, there should be some simple to use 'plug and play' general weapons; These weapons could be balanced weapons, with non of the benefits or trades-offs of custom weapons.
Some ways that such a system could work:
1) Multi-component structures:
(This is the method that From The Depths uses) While multi-component objects offer more creativity and involvement from the player, it is also complicated to implement and may effect performance. It would also need to be simple enough to understand the basics, yet allow for complex creations by advanced users. There would need to be a controller component which would keep track of the attached modules. Such a system could work and would be really neat but I'm not sure if multi-component objects is something that the engine supports (and it isn't worth adding for one feature). Another effect of a multi-component system is making weapons take up space, which would have a positive effect of preventing 'death cubes' (A cube construct covered in turrets).
2) Production-based customization:
Using a 'Turret Factory' a player could modify a turret's characteristics and/or model. This turret factory could be used to manufacture turrets (which players can place). Each turret could have a different physical appearance: A high ROF modified turret could have multiple barrels vs a sniper modified turret with a single extended barrel. The players should have the ability to customize each part of the turret from barrel length, gauge, count, etc. Since the turrets would be one component there wouldn't be a need for multi-component support and the performance hit would be the same as a regular 'non-modified' turret. The addition of a 'turret factory' would mean that a player could perfect a design then mass-manufacture and sell their design.
Both systems allow players to build weapons with different characteristics, and both would require trade-offs. For example: A high rate of fire turret would have a trade-off on accuracy, while a sniper turret might have higher damage/accuracy but a much lower rate of fire (suited more towards Alpha-strikes than DPS). Personally, I prefer the first method of multi-component constructions since it offers more creative freedom. The system From The Depths uses for it's custom cannons (advanced and CRAM cannons) is probably the best I've ever seen done. However, From the Depths is not a good example on the usability front, since it has a cliff of a learning curve and no real tutorial. I think a system similar to From The Depths would be a good addition although it may be to complicated to implement; The second method is a compromise in terms of performance/usability and creative possibility and may be a better fit.