Seeing inside when building in creative
Currently there's that problem if you have a ships with no large holes in the middle, you have no chance of seeing / editing blocks on the inside without stripping down the outer blocks. (especially a problem with small ships, as you probably make hallways in large ships anyway and you'd need to remove a lot of blocks)
So I think if you're designing in creative mode, there should be an option to see / edit blocks in the middle.
One solution would be is to allow temporary deletion of blocks in creative. Ie you would cut off a large part of the design as normal to see the middle, and after making some small changes in the middle, you'd get the temporarily deleted blocks back.
Another game From the Depths provided another solution for this: there's an option to make the blocks appear really small, so that you see through gaps between them, therefore you can see and edit blocks behind.