While they can be packed with useful things such as standard labs, drug production, moon miners, T3 production labs and reverse engineering labs among other things! They can also boast an impressive array of weaponry dealing fairly significant damage to a small opposing force and have a large amount of shield and armor hit points. But that's where the good stuff ends. They cost around 400m a month to fuel a large one. Even with hardener’s it's killable in under an hour with an average sized fleet of BS and guardians and even if a friendly fleet arrives it's hard to save the tower or even themselves if supers are on the field! In the age of super capitals POS stats mean little outside of wormhole space, there isn't much of a solution to this apart from drastically redesigning mother ships DPS ability or buffing the control towers with better base resists and HP in general. However I came up with a plausible solution and also one that is just plain stupid.
Ok so let's say we have a large POS under attack by about 50 Abaddon's and 10 guardians. The POS guns aren't breaking any tanks and your fleet of 40 BS only has 3 guardians. No way you'll out rep there DPS and you will all probably die. But here's where my solution comes in rather than buffing HP give the POS the ability to fit POS size remote reps! They'd have considerable resists and HP but not enough to stop them being killed by a good sized fleet and only allow say 4 anchored on a POS. Reps would be the equivalent to say 4 carriers with dual reps out of triage. This would provide a substantial increase in POs fleets survivability while not completely over powering them it would also allow some protection from super caps to your capitals if any and again without making it to OP!
The second idea was insane and stupid but we had a chuckle over it. Give the POS manoeuvring thruster's to allow it to move from its current anchored orbit point to another near the same moon allowing the POS to be off the warp in of the moon itself and possibly even off grid. This wouldn't be OP in itself because there easy to scan down! Second part would be to allow the POS shields to extend their power to aid another ship and only one! The POS itself would take 80% of the incoming damage while the damage it does receive would be increased 25% so its shields would go down faster than the actual DPS being applied! This would allow a little more safety to capitals jump freighters and super capitals while outside the POS shields while cyno ships would still be at risk seeing as 10 tornados hitting for 10k each would still hit for 2k damage more than your average cyno has!
I'll run numbers and better refine the ideas but I think as far as POS defence goes this would be epic without being OP!