One solution is to give these citadels the ability to disable the caps of attackers. Suck out all of their capacitor energy the instant the battle begins. If ships can do it, the structures should be able to do it. Or let the players store cap rechargers on a massive scale to allow the structure to keep its cap going. Or both! I can store several XL ships inside, but I can’t store a massive amount of cap rechargers?
There are ways to combat cap chaining. Make the fight hurt! If a group of ships can gank a structure, then the structure is sorely underpowered.
Which is why structures need to be able to fight like structures.
We’d be more interested in them if anything they discussed had anything to do with high sec. The response to this is always, “Go to null sec”