You know why those aren't free roam games? Because you don't progress on a free roam basis. Your path through the game is determined by predefined quest lines and hubs. It's not very complicated to understand.
[redacted] and you know it, the quest hubs in Elite will be stations, or maybe you get quests auto logged based on area
like in Guild Wars 2 and the like.
You need a bit more to prove that ED is not a themepark, sorry.
I'll call it a space theme park, because that's what it is.
It WOULD only deserve the label sandbox if they let me
1) build persistant stations in player contested systems
2) buy one of the 400 billion planets and build a persistant structure on it
3) blow one of the 400 billion planets up and watch the gravity in the system change
4) conquer and defend territory within player guilds
5) build up a trade armada
6) run a factory and produce goods, to sell on a player driven stock market
-> until then, SORRY. Space theme park adventure, fun, but no sandbox. Not even close.