When the capital ship entered your video card would fry. Space Engineers is a block (large and small build) by block game, and it keeps track of the damage to each and has to move each when the ship moves. That causes a ton of lag, which is why you rarely encounter busy space and why custom builds of large ships really stress your system with all the moving parts and gadgets x 500.
I would like the Stargate though.
In SE you are an astronaut, moving as you please and entering and exiting ships as you see fit. You can even move through space sans ship. In ED, you are the ship, nothing else. Despite the mouse look view of your "body" in the captain's chair, you are just the ship. You can never leave it. I feel as if they ever allow you to, you'll be the same control mechanism in a different ship, wheeled or otherwise, but you'll never be the individual. In SE you are the individual.
So making a game where all we see is our HUD all the time, no exceptions (other than debug mode and outfitting), into a "leave that ship behind and make another one" game would break the concept of the game.
I'd prefer to see 7 Days to Die with the ability to build something to leave that God forsaken planet to get to Space Engineers. ED is better as it is, with some tweaks of course.