I don't see why this is such a deep discussion on this board. It goes like this. EJ starts. Win or lose. If he sucks through 16 games, Marrone and Hackett will fall back on that as to why they should keep their jobs. The other scenario is EJ gets hurt. Orton either comes in and wins and EJ stays on the bench for the rest of the season or Orton loses and they put EJ back in when he's healthy and again, use him as the reason they should keep their jobs.
I would prefer if EJ comes in, lights it up around week 3 or 4 and stays that course and takes us to the playoffs.
But that's just me...