Honestly I don't think that we'll see Yavin 4 as a new planet (moon). I know that it is one of the most important planets (moon...) in the lore at this point, but it doesn't make sense lore-wise for Jedi to be there.
Master Gnost-Dural:
Did the spirit of Naga Sadow know of the Emperor's existence? Is it possible that there was some conflict between the two while Naga Sadow yet lived?
Though I must confess the temptation to visit Yavin 4 myself to try to answer these questions, I will not fall into that trap. Few Jedi have ever visited Yavin 4, and among those, almost every single one has fallen to the dark side. There are limits to the value of even the most incredible knowledge, and as a Jedi Master, I must content myself with trusting in the guidance of the Force to give us answers to these questions in due time.
I think that the best thing would be to have Yavin 4 as a flashpoint/operation planet (sigh... moon) because as mentioned it doesn't really make sense for Jedi to be there at all, but in a flashpoint/operation environment BW could make something out of it using the huge amount of darkside Force that consumes the planet. They could use the darkside corruption in order to create both great story and gameplay, i.ex you would have to resist/escape the corruption during the whole flashpoint/operation or during parts of it.
I'm sure that a lot of people would like to see something similar to this.