A major problem with them is that their guard setup isn't appropriate for a major city. They've just got a small amount of gunships loaded with very powerful explosives whose defenses are mediocre even in the Ungoverned Territories.

I've thought about a mod that solves this by having nearby CSCs and Militia stations send a squadron to defend Startons in distress.

Come to think of it, it might be useful to implement a distresscall function that any station can call when under attack, providing itself as a parameter. Any interested ships/stations could have an onDistressCallRecieved section that lets them look at where the call is coming from and decide what to do about it.

In case of Commonwealth, they need ion and/or thermo weapons to harm the worldship. Without them, Worldship can take all the time it needs to kill the station because TeV-9s do nothing to it. Gunships with few effective guns (e.g., Britannia and Manticore) get smashed with ease by the worldship.

I would suggest moving them over to EI Ion blasters in the lategame.

Upgrading at least one of the TeV-9s to ion blasters (and/or adding a launcher with thermo missiles) for CSCs may be a good idea too. Six Britannias launched by CSC get crushed by the worldship, then the CSC dies to the worldship. It may take a while, but the worldship will win barring player intervention.

In 1.7 Beta 6 I've added more hp and regen for large friendly stations (metropolises, shipyards, etc.).

This won't completely solve the problem, as others have pointed out, but I plan to solve the problem by having Xenophobes (and other wanderers) from engaging large stations like these (see: https://ministry.kronosaur.com/record.hexm?id=58438).

I think that will be better than arming up the metropolises, which would only lead to more Xenophobe wrecks.