R Dave Cartwright

Notice no one's tried to answer in 18 hours because the "Andy Reid's magical system" is a mythical talking point. He was a Holmgren WCO disciple who went to Philly and leaned on an athletic QB to make things happen out of structure. He compensated for underwhelming WR play (outside of the TO year) by using the RBs and TEs more as receivers. He shunned runs for screens (generally not effective plays) and horizontal passes. He got away from power running on short-yardage situations. This is why his offenses in Philly and KC before Mahomes were generally average at best on 3rd down and in crunch time when you need a QB to drop back and make plays that quickly move the chains in succession. And more often than not, Jim Johnson's defense was the better unit on those PHI teams, and the offense put too much responsibility on the QB in the playoffs, so they didn't win anything. He adapted some later like more shotgun with Vick and RPOs/motion in the Mahomes era, but his offensive system has never been cutting edge innovative. Reid is more of an early adopter and optimizer of offensive schemes. Not an inventor or revolutionary of offense. And without Mahomes last year, his system averaged 12 yards per drive. He also hasn't found a better receiving back for Mahomes in a decade than Jerick McKinnon, so they don't even have a Brian Westbrook type to get offense that way if they're not going to get much from the WRs. It's not a coincidence that Reid is the guy who went a whole season (2014 Chiefs) running an offense that couldn't get a single TD catch by a WR. It's a bug that he treats as a feature. To this day. And it's not going to change until he retires.