Not new, been asked for and answered by the Devs long ago.
They do not want to try to keep more than 1 BGS up and running that would evolve differently to each other.
And if they suddenly decided more than 1 BGS is ok, then all the "offline-gate" would spring up as one of the excuses was not wanting to try and keep more than 1 BGS up and running as it would cause inconsistencies between them.
Also having more than 1 BGS means people would need more than 1 save - which would kinda mess with the whole;
From the Kickstarter;
*And the best part - you can do all this online with your friends, or other "Elite" pilots like yourself, or even alone. The choice is yours...*
*you will be able to control who else you might encounter in your game – perhaps limit it to just your friends? Cooperate on adventures or chase your friends down to get that booty. The game will work in a seamless, lobby-less way, with the ability to rendezvous with friends
*Play it your way*
*Your reputation is affected by your personal choices. Play the game your way: dangerous pirate, famous explorer or notorious assassin - the choice is yours to make. Take on missions and affect the world around you, alone or with your friends.*
*You simply play the game, and depending on your configuration (your choice) *
*We have the concept of “groups”. They can be private groups just of your friends or open groups (that form part of the game) based on the play styles people prefer, and the rules in each can be different. Players will begin in the group “All” but can change groups at will,*
See that bit in red? It does not say you can change character at will, it says you can change group at will. Something that forcing more than 1 save on people would mess with.
Subtle difference I know, but it was there from the start.
Also, the "problem" we keep being told by open advocates is open "needs more players" - a second save on a new BGS would not fix that, in fact it would make it worse.
Right now, if someone wants to play open they can, but on a new BGS having to start again - some folks don't have time for that, so they wont bother.