There was a lot of discussion on the board about this on Sunday. Here's what I wrote then:
Why would we go three Defensive front players and only one O-lineman in the fifth round?
Our offensive line is very young. The average experience of the top 12 linemen - 3.25 years. This is before the draft.
The defensive front 7 is the opposite. The average experience of the top 12 in the front 7 is 8 years. Among starters: Carter (11 yrs); Chester (7); Bowens (12); Taylor (8); Thomas (9); Seau (15).
Saban realized that while Carter and Holliday are going to give us depth at DE and DT for the next year or two, he has to start getting younger in the front 7. That's not the only reason we went with Roth and Crowder, as well as Vickerson, but it's one of them. I think it was smart.
The thing I think we have to see is that we cannot rebuild every area in one year. And, He's not necessarily trying to get better at the weakest spot just for next year. He's trying to get younger and recognizes that there's a lot of age on defense. This is the Belichick model that he's following, if you listen to his press conference.
Back to the OL - I think we have a lot of talented youth on the OL that can get much better with the improved coaching (Houck)/scheme/offensive system etc. that are now in place. That's what Saban believes and I think there's good reason to believe this. The OL WILL be better. Even if it doesn't improve dramatically, he can make more improvements next year and now he has some youth to step in on the defensive front.
This wasn't going to be a completely re-vamped SB contending team in one year anyway.