My take is that ED has a persistence problem.
You need procedural generation (and thus RNG) to populate such a massive galaxy but, especially on this scale, is at odds with the needs of persistence. Persistence being characters, or places or pretty much anything that has some amount of state that carries forwards over time and is changeable in a recognisably meaningful way.
We do have this in terms of faction ranks but this doesn't do too much. I don't feel I'm building up a relationship with anyone in these factions, I'm not greeted with respect to my past actions in any specific way and my future actions will not change this. Stations don't change much (though the thargoid attacks have of course done this) and you can't, for instance, drop something on a planet and come back to it - things don't stick around..
So the world is very ephemeral.
So, if you want a personal narrative, which I think many do, it is a bit difficult to deliver within this. You can tick up a few counters here, you can unlock some things but I don't feel I'm really getting to know anywhere or changing anything much.
In some sense this is fine, but a bit more personal involvement would be good. It would be nice to feel a bit more personally known in my core allied factions and to be able to have longer term changes to notice.
I think some RPG light elements in relation to crew could do something here and maybe something extra around Engineers - that at least constrains where to do these things a bit. Maybe build out things in the contacts panel for contacts with allied factions that are outside the normal mission structure - something that might later lend itself towards spacelegs integration.
More ship related customisation and/or how they come - every Anaconda has those annoying wires? Why not differentiated wear and tear and idiosyncrasies (at least visually) in the cockpit so if your ship blows up the new one actually feels like a different ship. Have some wear and tear mechanics and more internal customisation.. Maybe do more will ship death and salvageable hulks - maybe you can go back and try to do something with your old dead ship..
Anyway.
Bit of a ramble
I think there are some relatively low hanging fruit here but, yeah, otherwise going to be tough. I hope FD can make some progress here, I think EDs great but it could be even better!