All of the Legacy Era crap about sith returning makes me wonder just what Anakin did. The prophecy was that he would bring balance to the force, nobody knows what that even means. Balance as in leaving only a Jedi? That doesn't seem balanced. Was it just to rid the Force of it's Dark Side? Then why do Sith keep popping up afterwards? How was being the Chosen One important at all??
I always thought bringing balance to the Force meant that when Vader killed Sidious that meant that balance was restored since the Darkside lost the very instrument (Sidious) which tipped the balance of power heavily in their favor. Plus he gave birth to Luke Skywalker who restored the Jedi order, tilting the balance of power away from the darkside.