I want to be serious about Peyton Manning for a moment. He's the ultimate system quarterback. And that system is the West Coast Offense. The best there's ever been in it, big arm, accuracy, great size, knows the reads, has seen all the defenses, etc. In fact, he's one of the better clutch qb's who's ever lived. His weakness is not himself, his weakness is the WCO. It's an offense designed to take what the defense gives. In the playoffs, teams with good defenses know this and then are willing to give only the underneath dink and dunk stuff. Everyone on the offense has to be perfect for 15+ play drives or it fails.
There's a new breed of offense that's coming, helmed by the likes of Andrew Luck and Bruce Arians. In their version of the WCO, everything's the same, except they will force the ball down the field occasionally, and sometimes, too often. This takes away the ability of the defense to sit way back and wait to tee off on the underneath guy. It's an interesting take on evolving an old standard.