I would like to see Ores being completly removed followed by a huge set up rework of the standard commodities. (This or Ores being seperated into different "profit" classes).
Also would love to see a proper GB balancing, the new shields were a nice addition, while other changes ruined GBs in a way. (Bring back the normal GB missiles pls, Titan's were a nice idea but they.. well.. bluntly said suck pretty much.)
Story wise? Well, I guess I would re-write the entire lore without Gallia but a re-appearance of the Sol Coalition (I still hate the fact Disco takes the extended unofficial destruction of Sol as canon) or simply make attempts to create less huge wars but more smaller short conflicts with visible but minor impact.
-bring back the old Spyglass battleship and make it a freelancer battleship
-new dungeon systems/uncharted systems with hard to kill npc's / boss npc's
-Horus to be made playable and the order strike back the nomads
-Imperial Yachts dusted out and made playable for all
-more alien presence pushing the houses, causing factions to put aside their difference and fight back