My first observance of his work was in 2001. He had just been hired as the OC of the Cleveland Browns, and I was very interested to see his version of the Colts offense there (he had been Peyton Manning's QB coach prior to the Cleveland gig). Many of the same ideas were in place, including the well documented "Shallow" and "Levels" packages. Some things I have always found interesting, however, are some less heralded aspects of his offense.
In studying the Steelers' game plan vs the Packers from Super Bowl XLV, these things become even more apparent:
Option Routes. Arians has always used a tough, dependable option route runner to move the chains. His use of adjustable routes separates on a regular basis is a real differentiation of his attack.
While I'm not certain how read concepts are grouped in the Cardinals' playbook, I do know that all the combinations I have seen have simple solutions using ACTS, the reading system described here. Further, this system of reading is producing great results on the high school level; new ideas are being deployed, and Part 2 of Developing an Offensive System will be completed soon.