I agree with you in that it has to be the OL. Specifically, tackle. The problem you run into with all offensive lineman is agility and strength. 6'8" 380lbs looks good on paper, but guys that big have to be freakishly strong to have the ability to move at the D1 level. Pass blocking is so important at the next level and a lot of high school lineman are not asked to do it enough. It's easier to find an interior lineman(G, C) because of skill required in blocking DT's & NT's. However, good tackles are hot ticket items like elite RB's & QB's, IMO. They have to be able to block the best athlete on the defensive line in Defensive ends. They need soft, quick feet to stay in front of the guy and great upper body strength to impede a bull rush while moving back. That's what separates the BCS schools from mid majors, IMO. Many of the interior lineman at BCS schools can play tackle at most mid majors. There is no vice versa....