Wormholes

Pretty much that. There has to be a cap on the amount that can moore else the system is just broken.

Unfortunately with that cap, comes the necessity for certain tactics to be redefined, such as structure blobbing (think protoss cannon rush), and bypassing and breaking the mooring system by allowing more ships than the structure was designed to hold, such as mooring then logging off, removing your ship from the system, but taking up a mooring bay.

You may wind up with 8 occupied mooring bays with no designation of whats occupying them.
You may wind up with people greifing mooring bays and never unmooring ships, taking up valuable space
You may wind up with people safelogging while moored, and if the system permits it, have a 300 capital fleet on 1 Hub all moored.

The system can work, but there will have to be some rules implemented for it. The main one and the one people are not going to like, is that the mooring system keeps the ship in space (allowing for people to scout and see what capitals are moored to a HUB, regardless of the person being online or offline).

People both want this and do not want it, based on their style of gameplay (I would not want my 3 Titans showing up as perma moored to a structure while I'm logged off because Derp my AUTZ internet). I would want this because I can see what numbers people have and where some of the capitals are stored, so I can design my attack, or create a defense (drag bubbles, sniping harassment fleets, bombing runs, traps, etc).

It can work, it needs work, and it also needs a commitment to stick to a design that some people, possibly a lot of people, may not wind up liking because Risk My Capital. There's a reason people generally don't leave a supercapital floating inside a pos unmanned (even if it is their own POS), but this is a different system and allows a person to more securely store a supercapital without having to worry about pos mechanics, securities, passwords, etc.

Can mooring work. I believe it can.