Farseer shows an opponent what is in your own deck. It would be a more useful card if they revealed your opponents cards. It would also make a lot more sense since she appears to be the oracle type and would be letting you know what the enemy has in store for you.
I don't like how Farseer reveals cards in your own deck to the enemy. I think it would be much more thematic to reveal the opponents cards. You could even give the current ability as an order and it would in no way be overpowered. The opponent may even regard the Farseer 'engine' as a real threat if they wanted to conceal their hand.
I would see game play as majorly enhanced for Scoia'Tael with a change like this.
A unique change where the 'engine' is information about what is in an opponents deck and what is not in their hand.