Hey there!
The ship building is quite cool, but I do have trouble upgrading ships as I advance in the game (new materials, new energy requierements, ...).
First suggestion is quite easy: There's already a button to change a block to another one, but this also changes the shape of the block. I think it would be cool if you could just update the material (e.g. iron to titanium), but keep the shape. This way you could select a section of a ship and update the whole section without acxtually caring about block types, corners, and so on.
Second point is a bit harder. How do people modify blocks that are completely surrounded by other blocks so far? I kind of dismantle outer layers of the ship to modify the inner parts of a ship (where I hide generators and so on), and then rebuild everything. That's a lot of work.
Only solution I can figure right now is, that either the editor itself identifies surrounded blocks and makes some space, access, by hovering the surrounding blocks away, or if I could select a bunch of blocks and move them temporarily away as one thing, or if I could make outer blocks temporarily semi-transparent to access inner blocks.