So I though that while we can customize our big blocky frigates and cruisers our fighters , rockets and stuff will remain pretty much uniform. While I understand it is too complicated to customize the model of the entity in-game I found another more achievable solution. The idea is that a pre-made mesh will receive different properties depending on what we want.
Let's say I want to build a new Torpedo. I go to a special block. A big crafting window appears with a big grid. I choose a frame out of those available (the base mesh with some basic stats) and the grid narrows to the specific frame of the torpedo (Just a long thin rectangle probably ...). I can put different parts in this frame such as engines, computers and warheads. We will make different requirements such as fuel and energy so there will also be need to put wires, tubes and stuff. When I'm done placing I will press "create" and get a ready unit with the pre-made model and my own properties (let's say I gave it two warheads, one explodes first to breach the hull and the other explodes in the hull itself. This also means we can set properties to objects in the greed such as fuse times and maybe adding condition gates). This way we will be able to get different entities.
Also a question - will turrets be entities ? If so they can also be crafted like that though I suggest using blocks for on-board systems and weapons when possible.