Everyone, including the devs, find the space piracy event of being a little bit lacklustre. It just triggers once and beyond that it doesn't do a whole lot. I play one of the big factions mods that include criminal cartels and now that factions are getting some love in the base game I think it could be the answer to piracy.
Rebels and slaves, at least in the flavour text in the recent dev diary, can siphon a portion of resources and use it for their plans. Include a criminal cartel faction that could trigger on planets with the right requirements (high distance to capital and high unrest). They can work to gain more members and have attraction like everyone else. If militarized and unhappy they will siphon more resources and start causing trouble on their planets, presumably how all the other unhappy factions are going to work. So not that different.
However there would be two major differences. First it isn't tied to ethos, just wouldn't fit in the current system. Unless you can sort of give weighted attraction. So perhaps individualist get the highest while the opposite ones to the government get a slight increase to attraction. Perhaps there will be a future update that will include misc factions such as this one. The second major differences is when this faction reaches its pinnacle of strength/unhappiness/whatever, they don't reveal the fleet and/or army they have been building with your minerals with the intent of carving out some rebel land. They'll reveal a pirate fleet/base in that planet's system (safe distance away), which will start raiding mining/resource stations and targeting weak targets and avoiding strong targets (essentially what they do now).
This way a criminal faction will always be an issue of developing into full blown piracy throughout your game.
Rebels and slaves, at least in the flavour text in the recent dev diary, can siphon a portion of resources and use it for their plans. Include a criminal cartel faction that could trigger on planets with the right requirements (high distance to capital and high unrest). They can work to gain more members and have attraction like everyone else. If militarized and unhappy they will siphon more resources and start causing trouble on their planets, presumably how all the other unhappy factions are going to work. So not that different.
However there would be two major differences. First it isn't tied to ethos, just wouldn't fit in the current system. Unless you can sort of give weighted attraction. So perhaps individualist get the highest while the opposite ones to the government get a slight increase to attraction. Perhaps there will be a future update that will include misc factions such as this one. The second major differences is when this faction reaches its pinnacle of strength/unhappiness/whatever, they don't reveal the fleet and/or army they have been building with your minerals with the intent of carving out some rebel land. They'll reveal a pirate fleet/base in that planet's system (safe distance away), which will start raiding mining/resource stations and targeting weak targets and avoiding strong targets (essentially what they do now).
This way a criminal faction will always be an issue of developing into full blown piracy throughout your game.