Defensive formation on 3rd and 16 in Eagles game.

Always? Maybe you can find a circumstance that you wouldn't. But with the clock where it was, the amount of time our defense had been on the field during the game and the desire to keep the ball in front of the sticks, zone was the right call today. Why leave it to a tired single high safety. I don't know what the argument for man coverage would be in those circumstances.
I guarantee you the same people complaining about this would complain if it were zone and they gave up a first down and later scored.