I feel that the Structure Blocks should be on a 'sublayer'; that is to say, they are lain down, and other ship components can be lain atop them without altering the Structure Blocks at all. As well, this would allow for a system where allied shots can pass over Structure Blocks instead of impacting them, which enemy shots already often do. this would also allow for things like 'half armor half structure' blocks, that are actually just an Armor block overtop of a normal Structure Block.
On the note of Armor Blocks; half-width Armor Blocks, akin to the half-block decal pieces, allowing for finer detail on armoring, or use as a cheaper, lighter armor alternative for smaller/cheaper ships.
As well, making the 1x2 Armor Slope in two pieces would be nice if you do the half-width Armor blocks.