His offense was positively unstoppable through the air, ranking fifth in the NFL in passing yards in 2007, and second in the league a season ago.
But Haley also had some of the better aerial weapons in the league in Kurt Warner, Larry Fitzgerald, and Anquan Boldin. The Cardinals' third wide receiver, Steve Breaston, amassed 77 catches a year ago, and all three topped the 1,000-yard mark.
Can the Chiefs make a claim that they have anything close to the weapons the Cards boasted? Matt Cassel had a very good season for the New England Patriots, throwing for over 3,600 yards and 21 touchdowns.
Those numbers were still well below Warner's. Cassel also had some pretty impressive weapons of his own. Wes Welker caught 111 passes, and Randy Moss hauled in 11 touchdown catches and over 1,000 yards.
The Chiefs' leading receiver, Tony Gonzalez, isn't even on the team anymore. Dwayne Bowe had a very nice season with 86 catches, but after him, the aerial production drops off precipitously.
In contrast, Haley's rushing offense the past two years with the Cardinals was absolutely abysmal, finishing dead last a year ago in the NFL in rushing yards per game, and 26th in the league in 2007, ahead of just the Bears, Lions, and Chiefs.
Haley's expertise has always been geared more towards throwing the ball, having served as a wide receivers coach and passing game coordinator in his stops previous to Arizona, which might be why he brought in former running back Maurice Carthon as his assistant head coach and kept Chan Gailey, who has an intimate knowledge of most of the players currently on the roster.
One player whose success or failure this season is very up in the air is Larry Johnson. After two straight injury-filled and disappointing seasons, he is truly the wild card in what Haley, Gailey, and Carthon do on offense.
Edgerrin James, at the tail end of his career, struggled mightily with Haley's offense in Arizona. Can Johnson pick it up quicker? Does he want to pick it up? There were rumblings not long after Haley was hired that Johnson wanted out of Kansas City.
Lately he's said all the right things about wanting to play and wanting to build a winner, but should Johnson return to either pouting or injury, the Chiefs will almost certainly become a very one-dimensional offense. Do they have the weapons to carry out a pass first, pass second, pass third, and then pass some more offense?
Is there a chance that will be the offensive approach even with a healthy Larry Johnson?
That remains a mystery, for now at least.