I think its unlikely that the sith empire could fall in such a way that it could be considered Canon in the terms of the Extended Universe. You have an empire that spands the galaxy that has brought the republic to its knees and yet is not even mentioned in any of the books. Because when they were written it hadn't happened.
So from that point of view trying to tie it in would be difficult. A little like where in the Heir to the Empire stories the clone masters are refered to as mad and the enemies of the republic but in the clone wars were the people that allowed the republic to fight. You can't always tie things in so as far as TOR goes and an MMO goes the empire could very much win.
It will never be Canon but then there are things in the movies that aren't even Canon, Leia says she remembers her mother her true mother, Obi Wan never remembers owning a droid that belonged to his padawan and Han Solo and Chewie who has travelled from one edge of the Galaxy to the other knows nothing of Jedi and the force yet they were only hunted down in his life time and the walking carpet knew Yoda.
So as far as the empire falling it may never be explained in the life of tor.
this is so wrong.
Leia says she remembers only bits and pieces of her mother and that she was sad in her memories. You CAN have memories from that long ago, FYI.
Han and Chewie travelled across the galaxy and never came across anything that made them believe some force was "in control of his destiny". HUGE DIFFERENCE from being in control of your destiny and the physical power of the force and the jedi.