For a long time, at any one time, there were two Sith and a whole bunch of Jedi. At the end of RotS, there are two Sith and two Jedi. I'd say he certainly did fulfill the prophecy. Like Yoda said, the Jedi just misinterpreted what "balance to the Force" meant.
This is exactly what I thought. he brought order, just not the kind they thought. He evened out the Sith and the Jedi.