Well I guess you have a point there. Yeah, I was looking and I can't make out the faces, but still, their resemblances are a bit more than coincidental.
If Kreia and Sion hinted at what was to come, they had to have had at least glimpses of this empire, I'd think.
Another thought: if exile faced visions of the past and present, what is to say that vision of Revan wasn't the future? Like the millenia old Sith Emperor waited, biding his time and saw an opportunity to turn the two against each other? Maybe they ended each other?