Expanding further on the hexagonal symbol. It's not outside the realms of possibility that Lucasfilm have taken a shine to this symbol and imagery and want to use it. Afterall, the EU isn't off limits if they see something they like.

The game is set 4,000 years before the movies, and this is the symbol for the ancient Sith Empire of that time.

It's sort of a precursor to the Galactic Empire symbol. They have similar designs except the obvious different basic shapes.

I don't know about you guys, but the symbol on the flag in the trailer seems to be a hybrid of the two designs to me. It utilises a circle within a hexagon, with a 'spoked' design just like the others.
Could this be symbolic of the Imperials/Sith returning to their roots?

I know this idea relies on Lucasfilm referencing the symbol from SWTOR (those who know the game will get it, those that don't won't care), but it just seems too perfect to me to be coincidence.

EDIT: Also, it's worth noting that despite being technically non-canon now (being EU) it's still a thriving MMORPG that's making them money. Tying elements of a game in with their new movies for the purpose of cross-promotion (even if its something as insignificant as the origins of a symbol) is exactly the kind of thing Disney/Lucasfilm would do. In fact they're doing just that already with the upcoming DLC for Battlefront that shows the player the battle that left all those derelicts on Jakku.