If Traya doesn't know of the Emperor's plans how does she know of Nathema?
That's the thing, everybody, NO ONE KNOWS what the Emperor is up to except the Jedi Council, Scourge, Revan, and the Jedi Knight! If Darth Traya knew about the Emperor's plan she would plot against him. Her far seeing abilities would not be able to see through the Emperor's future, I can assure you that. The point is, no one knows about his crazy plan and she loves him because he had the ability to eradicate the force. Keep this in mind, she hated the force more than anything, if she truly wanted it gone, then she wouldn't have minded the destruction of ONE planet.