David,
I agree that it would be easier to take the wings on and off with the servo in the wing, but the time you'd save wouldn't be worth having a servo sticking out of the wing in my opinion. Half the point of the system is that you've got a smooth airframe with no servo arms or control horns poking out anywhere. Some people don't mind, but I really don't like that on a jet. The first one I built had the tongue-in-slot thing and it worked fine. This new way is a tad more laborious to build, but worth it in the end, I think. It doesn't take any more time to slide the wire out, remove the flaperon and take off the wing than it does to plug in the servo wire. It's a bit more time depending on how you install your missile rail, though.