Indeed, this part may not happen in Q4. Id love it too trust me. But powerplay will go first if anything.
Then the balancing of player groups.
However, they have the chance to pull it off. They have to make changes to the BGS anyways if they want to keep having player faction interact with each other. Its only a matter of time.
Either that, or they halt player groups from fighting over territory. And thats not gonna happen.
Time is on my side here. Because of multiplayer balancing issues alone.
Its a reason a majority of people have quit this game after they reach a certain point. A lot of player groups are pretty unhappy with the state of the game when it comes to this.
I very much doubt that FDev would ever contemplate such a move. To alienate all the solo players and a large amount of private group players and probably some open players would not be good for the ongoing health of the game. In fact it would be utterly stupid.
I don't even think that they will make powerplay open only. They may make open more attractive for powerplay, but I think that is as far as they will go.