To make editing easier i was thinking for these,
[*]Orthographic Camera!!!
[*]The ability to load an image as the background/sides of the build space, with 1. would allow easy layout of ship designs. https://docs.blender.org/manual/en/dev/editors/3dview/display/background_images.html
[*]split view showing 4 windows that can be set to different focal points or angles http://www.bspquakeeditor.com/images/bspfull2.gif
[*]Ability to modify blocks that have been placed down, having to copy/delete paste just to slightly resize a block is annoying
[*]Grouping of parts, so we could select some blocks, group then move them around, as if it were solid
[*]Allow pulling blocks off and let them float, not connected to your ship, currently modifying the insides of a ship is very time consuming requiring deleting chinks of the hull to get at the inside, Reassembly Game has a nice 2D editor that shows these ideas (this is just the first video i found)
[*]First person camera so we could 'Fly' around the ship with WASD instead of the turntable we have now.
[*]Camera light, so we can see dark areas of the ship without having to exit edit mode then turn the ship to get better light
[*]Edit mode doesn't modify the live ship until you 'Apply changes', I get fed up of being attacked part way through a build and have to quickly drop in engines or guns to deal with it, with the edit mode separated we could build whatever we like, get interrupted we still have a working ship, also those annoying times where you delete your cargo hold and drop all your stuff in a cloud of boxes!
[*]Ability to 'Hide' selected blocks/Groups so we can get into the core of a build, maybe a filter selection to hide only hull blocks
[*]Visible Grid lines, maybe just around the cursor
[*]Auto grid, so as you zoom in the grid/block size shrinks to match meaning we could zoom in, make tiny changes, zoom back out and continue blocking out the ship without having to adjust things manually
[*]bind the block size and grid snap, so snap is always 1/2 the block size