The 2004 line was a complete toss-up. Wade Smith and McIntosh played LT. James and McKinney were the only real starters. The other side was manned by the revolving doors (figuratively and literally) of Taylor Whitley, Rex Hadnot, Vernon Carey, and John St. Clair. The line had no time to get together and play well. The line eventually settled on was very similar to the 2005 line and they played together well even at the end of the 2004 season.
The line last year was:
Damion McIntosh, Jeno James, Seth McKinney, Rex Hadnot, and Vernon Carey.
This line performed very well and was among the best in the league. Damion McIntosh actually was among the best in the league in run blocking. McKinney and the guards were somewhere in the middle, and Carey was somewhere in the middle. The 2005 right tackle/right end numbers were somewhat skewed by the pathetic play of Stockar McDougle. They were also very good at pass protection - this is helped by having a quarterback who knows how and when to get rid of the ball. Frerotte may not have been able to hit the broad side of a barn with any regularity but he did not hold the ball too long.
So, in 2006, what does Saban do? For starters, he lets McIntosh and McKinney walk. Fortunately - very fortunately - they both come back. You might think that we would be able to keep the entire line the same as it was last year. This only helps, as offensive lines have been shown to play better the longer they play together. Five average guys who've been together for two years will generally play much better than five all-stars who've never played together. Saban brings in L.J. Shelton, an overpriced free agent who's never really done well anyway and casts McIntosh to the bench. McKinney gets injured, which is unfortunate, but instead of replacing the center he replaces the right guard and moves Hadnot to center. Now, Bennie Anderson was pathetic when he did play.
The moral of the story is we should've had four untouched positions on the offensive line, with the only position being changed (C) out of necessity (McKinney's injury). Instead, Saban made some pointless moves leading to only two untouched positions. The net result as we all have seen has been one giant leap backward.