Is there any possibility that the power cores could become multiblock structures? ie. you build the reactor dimensions with various reactor blocks, and once you place the "core" all the blocks become a single reactor entity? The HP, Mass, Power-gen, (fuel requrements?), etc are all based on the initial block design, you would add an item that can convert the single reactor entity back into a block structure for editing purposes - this method could actually be used to great effect for all systems: build a cannon structure with blocks and once you add the "cannon core" all attached cannon-type blocks become 1 entity; System HP, Damage, Rate-of-fire, etc are all calculated once the system-coreblock is placed. I figure this would also improve performance in the long run, it should be easier to calculate damage to a few large entities over several hundred/thousand smaller ones
Additionally, I think it would be a good idea to observe modded Minecraft for how to consider power generation/transportation (I'm not saying make Starmade into a Minecraft clone, just to take note/inspiration from some of the most popular ideas of progression/automation currently available); There should be many different options for power gen, not just reactors: We're in space, what about solar panels? Sci-fi tropes like Di-lithium crystals? Dyson spheres being built around suns filling planet sized capacitors which wirelessly send energy to our ships through tesseracts? Power-gen should require fuel one way or the other, the free energy of a reactor as-is breaks the game; again variety is the key, everything from heavy/inefficient fossil fuels, more efficient liquid hydrogen, slow but reliable solar panels, powerful but potentially dangerous nuclear reactors, etc; each option which requires some kind of infrastructure to produce, and waste products to consider
The same philosophy should apply to other systems as well; have various forms of thrust each with their pros/cons, same for shields, scanners, cloaking, crew, etc. We currently have an almost endless capacity for creative design from an aesthetic point-of-view, it would be great to have a similar depth of possibility from a system design POV. Currently only weapons have this variety, and that is a shame in my opinion, when all systems could have this complexity
Finally, why not consider similar variety/complexity for item sorting, transport and storage? (although I do like Starmade's current storage system), we should have conduits and pipes transporting materials, not just wireless transport of everything (wireless transfer should be possible, but it should be a mid-late game goal for advanced factories with massive power generation) If you build a multi-tiered progression into the game it would have a lot more playability in my mind. As it stands now there is no reason for me to play this game in survival, as there is no progress besides just building bigger ships with the same systems over and over, the fun is currently in aesthetic design (creative mode), but the tiered progression would make me want to truly play this game
Just my $0.02 on the issue. Starmade has much more potential than Minecraft in my mind, but unless it can match modded Minecraft in terms of progression/complexity/variety/exploration the only reason I can see to play it is for the advanced build mode of ship creation; it doesn't stand up to survival game-play expectations in it's current state.