Maybe more limitations? it's pretty cool to have the max capacities of the ship increase cuadratically (both the max upgrades and max ammount of stuff increasing) . But the game basically boils down to whoever has more parts (and more upgraded) wins. One really can't compete to higher level ships when the stats increase cuadratically in relation to level and the way you build the ship does not matter much. The only interesting strategy i've come up with is having a really small ship with a lot of thrusters and mini battle ships so i can keep dodging everything while my ships slowly damage my enemy.
So far the only things discouraging you from adding as much parts as possible is energy constraints, speed and the constraints that come with leveling up. Ideally you wouldn't want the highest level ship to win every time but that's simply the case as of right now. Energy is not a problem since energy increases cuadratically and speed doesn't matter that much so really the only limitation is level. Ion cannons and are a step in the right direction since they make you think about position more than just ramming into your opponent randomly, however, it doesn't make much of a difference right now.
also, while the short description for the ship parts work great, i would like to know more about them, what's the difference for example between the 50 damage a void laser deals and the 50 damage a turret deals.
I imagine Space Arena: 1v1 Build & Fight is an inspiration for this game but if it's not you should check it out, its pretty similar and has more interesting parts in general. If theres something i would implement from that game here it's different types of thrusters (one for rotation speed and maybe another for warp drive). You could also make it so that some weapons can't damage the ship as long as there's some ship healh. and some weapons that can only damage shields