Its really annoying trying to figure out why ships would go to spacedock for repairs instead of a drydock. But I was thinking, you don't really see any workbees in the place, and it doesnt have the amount of lighting the drydocks had. Im thinking it might be a Refueling place and a place to park while the crew is on leave and etc. It might be that the drydocks stay so busy you have to keep them open as much as possible.
I really wish that the JJ Abrams movie would have shown this complex under construction or something. You know this Spacedock had to take a very long time to build...and I guarantee this monster was not constructed of the surface. NO WAY IN HELL!!!