Perhaps player v faction hostilities just start on a timer? 10 days or something?
e.g. "You have declared loyalty for <faction>. <other_faction> will actively expel you from their controlled space in <number of days>".
That sounds good.
Hm, what I don't like about it is that you have no choice in the matter anymore. Sometimes I care more about doing my own stuff than participating in my faction's silly (or scary) wars, which would be hard with that change. Bounties, missions or explorations that lead me into the space of the other_faction (which is in some cases almost everywhere) will become very hard to reach. This is especially true if your fleet is still small (you can easily get commissioned while in the starter frigate) and you can't really trade blows with other_faction's patrols yet. And that, after all, is the time where you most need the bounties/missions to grow.
I was thinking, maybe it would be enough if you get automatically dropped to "inhospitable" with other_faction, at which point your relationship to your faction is stable. You couldn't trade with the others anymore, but still traverse their space without being outright killed. Or you can actively decide to attack and take it to "hostile", at which point your faction might "welcome you to the war" with a reputation bonus (once per war). (Rewards are always more fun than punishments.)
It would also make sense for inhospitable (and suspicious?) factions to make random inspections even if your transponder is on (without the old waiting bar please) so smuggling in their space gets a bit more exciting.
It has already been discussed a dozen pages ago but I'd like a way to tone down or maybe filter the explosions.
Got to "C:\Program Files (x86)\Fractal Softworks\Starsector\starsector-core\data\config\", open the file "settings.json" with a text editor and find "enableShipExplosionWhiteout":true. Change it to false. VoilĂ