I really don't know if AJ could play DE--he hasn't shown a
consistent ability to get off of blocks well...I personally think he's a tweener--he REALLY can't cover at all--but maybe better suited for the "Mike" LB in the 3-4...
You don't have to line a guy up in the "traditional" FB position to utilize him as a lead blocker--'ol Gus is proving that to be true. And I do prefer utilizing a FB.
Let me say that it is a matter of philosophy--and it appears that CBJ and Bajakian DON'T favor the use of lead blockers in their offense. They will bring their TEs down to PREVENT the back-side OLB or DE from crashing down to blow up a play, or to fill behind a pulling guard or tackle--but they don't lead the RB into the hole.
However, if you want to control the clock, establish a power running attack, and utilize play-action passing--AU, Bama, LSU, and Stanford are the textbook examples--and they use a lead blocker, whether he lines up as a FB or as an H-Back. And, AU's record of success running the ball stands for itself. LSU's offense is probably the more TRADITIONAL example, but they both do a great job. And that red team is pretty good running the ball, too.
Fla blew our game open last year by running a similar play to the first one highlighted by Carner from the AU game. They inserted Burton and ran basically the same play Auburn ran against us all day. They pulled a guard and used a lead blocker to the weak-side of the defense and Burton popped through the hole and outran everyone to the endzone. (here's a good view of that play:
2012 Florida Gators vs Tennessee Highlights - YouTube
check out the play at the 2:44 mark. Notice that our #94, Sentimore, collapses in the hole instead of getting driven out of it like McCullers--that's all he can really do in that situation. But he would have been driven out if he had stood up like McCullers. AJ reads the play and scrapes over--but doesn't keep his outside shoulder free and gets taken out by their FB.)