That's very valuable feedback, thanks. The numbers sound odd, though. The spawner's AIPerGuardPostShipCap is 2, and they don't use unit cap scale. How many guard posts and how many spawners, exactly?
But in general I'm leaning towards doubling the "reload time" and doubling the lifetime of the blades (which doesn't directly increase dps but does make them less dependent on quickly getting a target list).
I think about 10 guard posts on that planet, no time to look now - and both AIs have them, so 4 per GP. And there probably were some free ones, too.
I did a test, most blades I saw were reaching my blob with 20-50% health left.
40 MK IV spawners generate blades with 4.8m health per second, so I need 1-2.5m DPS just to not take damage. Add in overkill and I would say its 3.5-4m just to not take damage from 40 ships.
Even with only about 10 spawners and a few other ships left, my fleet of 1000+ ships, starships, spirecraft and golems was unable to intercept all incoming blades due to their speed, every few seconds one or two would get through and do damage.
I think the main reason that makes them feel so strong is that the blades have practically sniper range, so you have to fight all of them from the time you enter the planet.