I'm enjoying this mod, but I have noticed a couple of balance concerns with settlements.
Having just the one, obviously you want the effects to be reasonably strong, but they are -very- strong for really very little investment. This could be 'fixed' by lowering the number of structure slots at a settlement, but I think that would make it less fun. They're as strong as a full skill point at least, and much easier to access once you have a little money. Perhaps we could get config settings to pick between a range of strengths for them? (I'd go for about 50% myself I think) I know config options are a pain, sorry, but I felt I should ask.
Here's one combination that I think ought to be changed either way though - if you have a storage, storing things is free, and it also generates quantities of supplies and fuel for you. The issue is those are free to take, and it generates them reasonably quickly. Especially if you ALSO have a trading post, where you can sell things at effectively full price (-20% tariff), you can end up visiting your settlement, not needing all of the supplies, and selling off say 650 supplies for ~50,000 credits, effectively free since it'll generate more later, with a startup cost of only perhaps 200,000 credits on top of the settlement cost itself... and you're getting other benefits as well! This also applies to fuel and heavy machinery, of course.
I don't think the generated supplies and fuel ought to be free - most likely the free now, pay later approach like a waystation or outpost from nex or most of the other supply generators would work. Thing is, you've almost certainly thought about that and decided it wasn't a good approach. Do you feel like explaining why not? Another possible idea is to reduce the cap on generated supplies, or perhaps make it tied to other buildings - maybe the storage on its own only generates 100 free supplies, but it gets +100 for trading post, +200 for logistics base or industry or whatever makes the numbers work, and similar for fuel and machinery.
Another alternative solution might be to make a submarket -just- for the generated supplies and stuff, and have them a lot cheaper than usual but pay-now, maybe closer to 50% cost instead of nil. That would still make them cheaper even than a waystation's pay-later supplies, but without making the large quantity of them such a big deal?
In counterpoint, the actual passive income generating parts of the settlement are very weak - even settling on a fairly good rare ore vein (instead of ruins, which I now regret having got a bit of experience with the mod, but that's fine!) my settlement could if I focussed all the slots for it generate maybe at most 30k a month passively... I'm reasonably sure that I can get way more than that selling supplies, fuel and machines back to its own trading post every month, though I haven't measured it so I could be wrong. Still though, the refinery feels like a pretty wasted slot with a massive payoff time given it's 100k to build it and then won't actually pay itself back for over a year and doesn't really do anything else... No ideas to 'fix' this though (if it even needs fixing), because I get the sense the settlement shouldn't be as good at this as a well built colony, and I agree.
I think calling it a settlement is a little weird to me as well, since it's so focussed around supporting the player's fleet rather than being a place of its own like a colony already is. Might it be a better idea calling it an operations base or something? Would also make it fit flavourwise better with how you can place it onto a world owned by another faction, which is a feature I love!
I haven't found any hull alterations or ventured into the abyss yet, but I'm looking forward to that as well, and I'm enjoying the additional exploration content and the backgrounds!