Similar Sandbox games where for example the Elder scrolls saga (Morrowind / Skyrim). Some people - including me - loved them to death (much much more than Dragon age for example) cause you can project your own fantasy into the game. It has plenty of immerive things like caves, beautiful landscapes and sceneries. Small towns bigger cities that all scream: "Mysterie".. in TES Games you dont follow a narrow road, you are more like an explorer - you find stuff by chance.
now translate this into a space sci-fi game and you have Elite. With more time Elite will get more features. Of course a 100M $ game is more fleshed out from the start - but Elite also comes with modding and already lots of plans for features after the "release".
The only thing missing is a single player story, but only some people will miss this - its nowadays modern for games to have an SP part (even the Battlefield Series got one..). Maybe instead of a SP story they could implement smaller missions that build up etc. - but for hardcore fans thats not needed.
Maybe more space ship customization will help to increase immersion. Custom Huds, colours, shapes etc.
To come back to the initial comparison with TES: what made people explore the TES world? it felt big, but it was very small, you only had to walk 5 minutes to come from sunny sommer to icy snow mountains. Whereever you went there was some sort of "atmospheric" beauty to it - and of course caves / riddles / mysteries to solve. The more "options" you have while walking / flying around - the bigger a "level" feels..
For Elite this could translate into Options coming up while in SC. WHat we have now are options: distress calls, Warzones, Interdictions etc. But what they are missing is - they dont feel special, they just pop up. Maybe add a little minigame to them etc. Find special point of interests - interdict traders etc. Stuff that makes the player feel and believe that what happens now is truly special and not some random option from a list. Maybe a different visual style would help too - while in supercruise we have a super sharp pitcture of the system with all lines etc. - why not make the view more blurry - while in supercruise we are faster than light, maybe we shouldnt be able to see such great detail (maybe for starter systems that are well cartographed such detail is okay - but for far away systems we shouldnt know so much - instead of planets we should see center of gravity and blurry colours etc..)..
So in my eyes its more a thing of "presenting" options rather than the options itself or the amount.
- what you should do is to believe / feel immersed. The game helps to an amount, but you have to invest too.