The defensive line is the lynchpin of every defense.
A strong defensive line will force a weaker offense to utilize their tight ends for blocking assignments. A weak defensive line will allow the TE to run his seam routes. When the TE runs free, then the middle linebacker has to chase him, and this opens up the vulnerable heart of the standard 4-3 defensive allignments.
A strong defensive line forces a fullback, or running back to stay in for protection.
A strong defensive line disrupts the rhythm of the quarterback.
A strong defensive line shortens routes.
A strong defensive line limits what a running back can do.
The best part of a GREAT defensive line is that it "protects" its linebackers in much the same way an offensive line protects their QB. When the linebackers run free, then an offense is compromized. The defensive line is the linchpin of any great defense.
THE MOST UNDERRATED ASPECT OF FOOTBALL HANDICAPPING IS DEFENSIVE LINE EVALUATION.
With that being said, let's look at a weak defense:
Arkansas was the worst defense in the SEC. They allowed 42 touchdowns and 4,500 yards. When you compare it to the 14 touchdowns and 3,100 yards allowed by #1 Tennessee the contrast can be stunning. Why was Arkansas so bad?
You can trace it to the defensive line. This unit is highly undersized with Adrian Davis pushing 250 pounds on one end and two tackles in the 280-290 range. There won't be a pressing need for any offensive line to double team on the inside until Petrino's recruits get settled in. Arkansas was outrushed by almost 60 yards per game last season, and the 2009 version of the Hogs looks just as weak as the 2008 unit.
I mentioned a 250 pound strong side defensive end in Arkansas. He's backed up by a "Sam" Linebacker that weighs 237 pounds and an MLB that weighs 222 pounds.
*What are they going to do when LSU runs a 315 pound right tackle and a 233 pound tailback down their throats? Oh, let me see.....last year LSU ran the ball 44 out of 65 times.
*What are they going to do when they face Alabama's 305 pound senior right tackle? Let's see.....Bama only threw the ball 15 times in the 2008 meeting.....They gained an average of 9.4 yards per carry!
I suppose I'll keep this short by saying:
In most cases....when there is a vast inequality between opposing lines, the gameplan will already be in place for you! SEC teams are no different than any other college team. Their coaches will seek the path of least resistance. FIND THE MASSIVE IMBALANCES AND YOUR JOB WILL BE EASIER.
Also remember: Totals can be assessed with this imbalance in mind. Alabama scored 49 points in that meeting with Arkansas, but they recieved the benefit of 2 interception returns for touchdowns and two huge rushing touchdowns (82 and 67 yards). The 49 points is misleading. MASSIVE LINE IMBALANCES WILL INDUCE TIME CONSUMING DRIVES! (The life gets sucked out of team totals for weaker defensive teams: less possessions for their offense, and a fresher opposing defense.)
This is one facet of football handicapping that occurs less frequently in the NFL, but it pops up all over the board on Saturdays. One can certainly argue that the run sets up the pass, and therefore totals can still rise, but in college the trend toward increased passing due to run success can be less influential.
*Even Tulsa ran the ball 47 times against Arkansas in 2008.
I hope this helps (I may try to find games where imbalances are pronounced).