Well wasn't it a thing you needed munitions to replace a WP backs when they first were introduced?
I suppose it might work well to require something like 100 units of munitions to be consumed every time a WP was taken out and replaced. So 1000 munitions would give a single WP 10 respawns, and so on. The module slot itself could stay indefinitely, it just wouldn't lay a new one until the commodity was back up.
So during a base siege the defender would need to eventually run for more ammo or have it shipped in, and the attacking side could eventually gain a better advantage by prioritizing around the WP's first. I suppose that doesn't help the odd passing trader who gets annoyed by them if they pass too close, but you could then just come back in another (capital) ship later (drop an attack notice), and start knocking them off slowly, even for something to do. I wouldnt make it too easy though. Then at least its something that makes players trade more for defense, and becomes another valuable cunsumable. Inrp laws might make a demand for munitions touchy too.
I don't know though if thats easily doable but it doesn't sound impossible. And then Agiera would have a boom in munitions customers. Even BMM's could be a cheap 1/2 rate ammo, illegal option' and thats if some factions don't sieze munitions on sight as a policy.