A fairly big non-spoiler is that we know what happens to The Empire. Something like 800 years after TOR is the Darth Bane era. By that point there isn't a unified Sith any longer and the pure bloods are extinct. From the books we more or less how it happens too. There isn't some big climactic victory for the Republic, the nature of the Sith is their undoing. They fracture into a dozen different Sith Orders who all turn on each other and give the Jedi a chance to get their act together. The Dread Masters are the beginning of the end of the Empire.
It will still be fairly cool to see how it all goes down though.