What are you supposed to do for one way trips? What if I am booking a multi-city flight? What if its an award ticket with miles? What if I want to check first class flights only? Flights with fully refundable fares? How do I check fares for children? What if I want non-stops only? Have you tested your "when" box with users? I can guarantee some of my less technical friends and family members would have no idea what to put in that box.
If you want a simple tool, fly an airline that has simple routes. All of you who love Southwest, go fly them. No one is forcing you to fly American. If you don't think they are providing shareholder value, don't buy their shares.
Anyway, like I said, nice PR. You suckered me in.