That's pretty much exactly what I've meant. I think that some sort of "Gatekeepers" system combined with Sector evolution mentioned by Alex would create an amazing milestone-style progression during the middle parts of the game. Actually, Starsector already has things like that, with examples being the mentioned Red Planet, Cryosleepers and even the early resource gathering phase before the player is able to do any substantial exploration. I simply think that the challenge behind all this things makes the rewards feel much more valuable.
I think that a good example of this milestone progression is Terraria, where the gameplay loop itself is pretty simple and consists entierly of resource gathering, exploration and boss fights. Terraria's progression structure is very much based on the concept of gatekeepers. Each time when you progress you are faced with a challenge that you need to overcome, and with each challenge come both vertical (opening up of new potential challenges) and horizontal (new tools and resources, new ways of solving problems) progression.
I think what makes Starsector a very unique game is the potential of integrating some system like this, maybe in less limitng fashion, and consistently integrating it in both game lore and narrative. The game taking place in basically what is a part of ruined, decaying super-civilization opens up amazing possibilities for different small stories about legendary spaceships, planets, both planetary and orbital facilities,quarantine zones, space monsters etc. Having all of this combined with the Sector evolving as the player progresses through the game would create absolutely exceptional exerience, something that hardly exists in any currently available videogame.
^I like where this thread is going. I'll throw my opinions in as well. The above pretty much sums up my thoughts about how I would find the most midgame fun before really setting into the colony game.
I don't know that I'd define progression in terms of being able to move further and further way from the core, though, hmm. I mean, that's not necessarily wrong, but progression could also take the form of successive expeditions becoming more difficult based on the player's actions/the evolution of the Sector.
There was a really old game for Sega Dreamcast called Armada that took this approach. It was simpler than Starsector since it was designed mostly as a pure arcade shooter rather than an adventure game, but was very addictive and fun. You could travel as far from the center as you liked and the enemies seemingly never stopped scaling in size and difficulty. Enemies would also vary in tactics and appearance based on the direction you took.
Starsector is set up that it could very easily work in at least a similar way. It's a simple design as far as scaling goes. Though that's not necessarily the
best way in every case, there are some compelling reasons for it.
Mainly, for me, it is about this design being naturally intuitive and that this design allows for loot to also scale with distance. I would appreciate this from a gameplay perspective both because I dislike finding an amazing treasure trove like a weapons cache relatively close to the Core Worlds as far as difficulty consistency goes, and on the other side of the spectrum finding poor loot in a far off system can be a little underwhelming for me considering the relative cost/risk between the two expeditions. The reason why this also makes sense from a lore perspective is that if you as the player can salvage things, so can others and so the closer to the Core Worlds you are, the more picked clean of good technology it gets.
Now that doesn't mean that everything near the Core Worlds needs to be boring and everything on the fringes should be filled to the brim with loot, though, like this design might imply. That's where the gatekeeper idea comes into play. In particular, I think it would make sense for Hegemony fleets to guard the entrances to warning beacon systems. Since according to lore the Core World's public isn't supposed to know about them, it would make logical sense that they would be guarded from scavengers in order to keep a lid on the existence of REDACTED. The defenders would be static guardian fleets (sometimes boss level officers/etc) that would seemingly "resupply" when the player isn't around (handwave handwave). Other kinds of gatekeeping can be added for variety too, of course, but this is a feature already implemented that could be adopted to this idea.
(I also think it would be very cool to be flying by one of these systems and suddenly see the guardian fleet get jumped by an Ordo or something. Maybe that would have to be a rarer occurrence but it would certainly be interesting)
Now, reasons that could make the alternative complicated, at least to my mind:
progression could also take the form of successive expeditions becoming more difficult based on the player's actions/the evolution of the Sector.
I know this is just a general statement and there are probably undecided details, or I am making assumptions about implementation etc, but this sort of difficulty scaling can be really tricky to implement in a way that doesn't inadvertently cause difficulty spikes.
1) The information about what causes these difficulty increases has to be very explicit. That can be hard to do depending upon how isolated the difficulty increase is for the various campaign things the player can do.
Example: In Oblivion, for instance, leveling increased the difficulty of the monsters relative to the player, so as you play the difficulty naturally gets increased. There were two big problems for me with that scaling system. One was that certain quests (Oh I hate you Kvatch!) would scale to become practically unbeatable if you leveled more than once or twice. Two was that if the player didn't know exactly how to increase their own power to match the new enemies, the game got exponentially harder rather than a linear progression of difficulty most players expect. Now I'm definitely not 100% sure on this, but I suspect this could already be happening for players who focus on pirate bounties and then have a harder time with raids and raider bases later on as a result. (I know the bounties scale by beating them, but also iirc this also ties into pirate patrols alongside the standard sector time factor? It's a dim memory of reading something before so please correct me if I'm wrong.)
2) Even if the information about how this works is explicit, having (for all intents and purposes) a "timer" to the campaign's difficulty might cause some players to fall behind the curve or get locked out of features because they didn't invest well enough into them early on. It takes away the ability for the player to plan, because they are on a clock whether literal or in the sense that most actions they perform contributes to difficulty. Some games make this work very well anyway (XCOM, Majora's Mask), but it is a subjective feature that can become polarizing to some players. Just my two cents.
All that being said, I'm not saying its impossible, and this doesn't touch on quests or story arcs causing these kinds of difficulty increases either. Those particular kinds of difficulty levers are usually exempt from the above problems because the context is almost always explicit and the player has the option of when to pull the trigger and increase the difficulty, so to speak. Even that option can cause frustration if the player doesn't realize it locks out or greatly increases the difficulty of other things they didn't expect.
I'm not so sure about them being non-combat dangers, but that's just a detail.
I certainly wouldn't mind a few non-combat hazards like previously suggested superstorms or something, but I wouldn't want to be forced into them unless I was willing to risk it for a great reward.