Defense will still be very good. Rashad will be the biggest loss obviously, and will be missed. It isn't out of the question that Cody could go pro. If that happens, he'll be missed. But the defense is in really good shape.
On offense, we have to replace JPW. Gonna likely be some growing pains there. The bad news is, we'll be replacing 3 future NFL offensive linemen (2 of which will be highly drafted), and Travis McCall who is as good a blocking TE/H-Back as there is out there. The good news here is, we have a lot of young talent on the OL, and those guys have gotten some snaps this season and should get more. We have quality depth there, but again, other than Johnson and Drew Davis, we'll return very little experience. As for McCall, his lead blocking will be missed, but Colin Peek becomes eligible next year and he will give us a tremendous passing threat in the 2 TE set with Walker. Saban loves Peek, and he very rarely publicly praises a player like I've seen him do peek a couple of times. We lose Oakley and Stover, and of the 2, Stover is the biggest loss. Good WR and good blocker, but our depth at WR is going to be excellent.
On special teams, both Tiffin and Fitzgerald return for their Sr seasons, so we are looking good there as well.
In conclusion, the biggest area of concern is getting a new QB in there and putting a new OL together. The good news is, we have the players now, and more on the way. I think we'll be better on defense, better on special teams, and have a slower start on offense but improve as the season wears on (as the QB and OL get more experience).