And this is what I try to tell people who say 'increase PP NPC numbers'. You can't, because the spawn rates would change. The BGS too is interesting but also annoying in that it works to antagonise.What really ticks me off about PP, even though it is opt in, it heavily impacts on certain game aspects if you don't play.
2 points specifically come to mind:
Bounty hunting, where PP ships spawn in large numbers, taking up spawn slots, meaning more down time in nav becons/RES waiting for pirates to spawn. Prior to PP you'd get a nice constant flow of pirate ships. Since the advent of PP, half the ships in any given area can be PP ships, slowing down the spawn of pirates.
BGS - powerplayers will sometimes try and flip a system, not because they care about the system, but just because its the wrong government type for them. They don't care about that faction that gets in charge, as long as its of a type they need.
I'd much prefer happiness to be based on state rather than gov type- so then it comes down to how content your citizens are. And since PMFs want harmony they'll be keeping their systems happy, and that attacks by others destabilise in a BGS way that is natural.