My thoughts on this, is that Anakin did bring balance, but not in the expected way. If you think about it, the jedi held power for 10,000 years after the great jedi vs sith war. Now take that into account and the fact that it takes longer to create than destroy and also the fact that jedi gain power slower but once they reach their absolute full potential, they are more powerful than the sith will ever be (NJO's Jacen Solo is an example).
So the jedi have been in charge for eons, and the sith are in hiding to gain power through deception and murder. Not much balance there at all. Now in comes the chosen one, expected to destroy the sith. What if the prophecy ment for him to destroy the jedi to balance the equation in terms of what is achieved in the galaxy and how the lives in it are affected.
For instance, 10,000 years of creation by the jedi, destroyed by 30-40 years of sith rule, and it is still challanged after Luke sets up the academy. My idea is that the balance is not really between the orders (Jedi/Sith) but of the lives affected by who's the strongest. The cycle of life and death, despair and hope.
Follow me on this one, Jedi/Sith war, then Republic/Jedi Rule, Empire/Sith Rule, New Republic/Jedi, Emperor Reborn, New Republic again-peace with Imperial Remant, Yuuzan Vong invasion, Galactic Alliance, DarK Nest trilogy, Whatever happens In the new Legacy series.
See the pattern?. The continuing cycle of life and death. One can argue that Anakin fullfilled his destiny of bringing balance to the force by having Luke and Leia with Padme. Which in turns leads to the continuance of the Skywalker line and they are the ones that fight off the reccurance of the darkside (evil) in all of these events.
This is my idea of the prophecy LMK what you guys think.