... From the linked blog post (under "Slipstream layout generation"): "First off, slipstreams are dynamic – there isn’t a single fixed layout. Instead, a new layout is generated twice per cycle"
So I don't think Adjusted Sector will need to take them into account at all, since the slipstreams will be overlaid on top of the map during gameplay rather than being a part of it from the start.
Wouldn't that cause stars to be generated under the streams, either causing them to be inaccessible or causing the stream to "break" all over since according to the blog:
...slipstreams are interrupted when crossing hyperspace areas occupied by star systems...
Which would mean if enough stars are spawned the streams would be too short and useless?
The bit I quoted in my earlier reply says, pretty directly, that slipstreams will change position as the game progresses: "There isn't a single fixed layout." "Slipstreams are dynamic". "A new layout is generated twice per cycle".
Slipstreams most likely don't exist at all when the stars are placed, because that would make the code more complicated. There would need to be code both for placing stars away from streams during map generation and code for creating breaks in streams as they're dynamically placed/repositioned every half-cycle. Much simpler to wait until after the stars are placed before even thinking about slipstreams, because then you need only the "creating breaks" code and not the "placing stars away from streams" code.
But, yes, you're right that, based on what we've been told so far, if there are too many stars then the slipstreams will be broken into very short chunks that aren't very useful. But that's all happening after Adjusted Sector has done its thing and the game has started. AS could try to leave larger open areas to allow space for slipstreams to stretch across, but it doesn't look like there will be any way to know, at the time that AS makes the map, where the slipstreams will be and avoid them.