Another bad argument.
Our offensive line was a great run blocking unit, they played great football. But they are not a historic offensive line, there have been countless RBs throughout history running behind great offensive line. 20+ plays by an RB or them taking it the distance doesn't happen often, no matter the offensive line.
Lesean McCoy ran behind one of the better offensive lines in the league in 2013, guess how many 20+ plays he had? 9. Adrian Peterson, outside of 2012, when he was running behind a top 10 offensive line, averaged about 8-9 20+ yard plays.
Demarco Murray had 15 20+ yard runs last year, Peterson MAY have had a few more; but I'm willing to bet he'd have around the same average as Murray.