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.
A change like this is also more thematic.