I think they miss him. No question. He's a good interior defender who can play the run and rush the passer. But I think what happened to them last night defensively was not at all an "if only we had SJD in there" night. They were collectively mauled. Miller said something along the lines of "we hit guys at 3 yards and they fell at 7" and that's absolutely true.
Turnovers. Drops. (ill-timed) Penalties. Missed tackles. All those are things you don't figure out
how to fix, in my opinion. You decide TO fix them- or not.