It's always been overrated. I will always make the argument that Emmitt made that oline more famous than they actually were. None of those guys were Pro Bowl players before Emmitt got to Dallas. That stupid documentary, Great Wall of Dallas or whatever the hell it was called was one of the biggest propaganda pieces of garbage. I never watched it but it made it seem like those guys were Hall of Famers when in fact NONE of them were. Yes I know about Larry Allen but his rookie year was 1994, Emmitt had already won multiple rushing titles by then.
Furthermore, I have watched a lot of 90s Cowboys videos on YouTube and I can't tell you how many times Emmitt made the first few defenders miss, how many times Emmitt broke tackles or avoided being hit. Did he have huge wholes on some of his runs? Of course he did but it wasn't on every run like everyone makes it seem. He also had runs where he could have lost yardage and his shiftiness and elusiveness was on full display. Emmitt had great vision and is one of the greatest running back in NFL history. McCoy is a footnote in RB history. There isn't a single run or moment where I can remember from his career.