Given that the New Earth Space Dock was tied to Earth's Planetary Grid for a unified Defense, it stands to reason that they don't want it to be "mobile".Sure, I guess it just depends on how mobile you want the base to be. If it's a situation of being "mobile" but more of a long-term solution, sure. But if you want the base to be a truly mobile starbase that can essentially move on command as needed it would be better for it to be able to move on its own. I was going to suggest that perhaps rather than built-in warp drive, it could just have dedicated warp tugs but... at that point it's the same difference of just having its own drive.
The advantage of Fortifications / Emplacements is that you know they aren't generally going anywhere and are there to protect you.
When designing Fortifications, the Venn Diagram of Offense/Defense/Mobility of where you put your Points/Tech in, since you don't have FTL, you only have STL maneuverability, then all your points goes into Offense/Defense and your Fortification can become "Beast Like" when we see the New Earth Space Dock hold out against a Hi-Jacked StarFleet Armada for hours on end.
Or a Universe Class like the Enterprise-J is effectively a Mobile StarBase, in StarShip form.I'm envisioning something that is more of a truly mobile starbase that tends to not spend very long in any given location... otherwise just build a starbase.
Isn't that what a giant Dry Dock is for and then having tugs move it into position.Or perhaps even this mobile starbase is a Kurlan Naxos of starbases where it's primary function is moving in and... building a starbase. It's like, a starbase carrier.
Imagine how much easier it would be for "Re-Positioning" if they had Spore Drives and a Biological Navigator.
You build the StarBases at a giant Factory Yard in space, than "Spore Jump" your StarBase to it's intended location and align it with the appropriate Lagrange Point.