My suggestion is simply - delete the plugin. Yes, this hurts. But as we all witness it's broken and, I believe, unreal to be balanced in any way around. If the base is too strong then the attacking party will not like this because they need to gather a forces that are crushing the server to even try while defenders just need to make sure the base have supplies which can be done by 1 player, really. If you'll make them easier to destroy then the building party will not like this because bases will be dead in no time with a lot of time invested wasted. And the problem is that the edge between OP bases and useless bases is very tiny and, in fact, can't be found in any real frames of time.
So it's easier to let this plugin go with light heart because it failed. While the POB plugin was off the player count was actually higher as we even managed to hit 170+. Now it's on and it's barely over 100 in the weekend evening.
Let it go - yes, the idea was interesting, the time was consumed, the future was painted as bright and happy. But it's easier to let it go now then to fuck with it another few months and to do the same there.