There will probably never be a significant price drop. You'll see maybe at most a $30 reduction, then the new cards come out and they stop making the old ones. If you are lucky you can find a clearance sale for the old cards when that happens and get them cheaper but at that point you could just buy 1 of the new cards from a lower tier for cheaper at the same or better performance
So don't bother waiting for a price drop.
Black friday/cyber monday is the best time to get a cheaper 1070 but don't expect them to be $350, 10% off is the most you would see. Since that is less than a month away I would say its worth waiting but don't wait any longer since you won't see better prices than that until the next series of cards is released, at...