An offensive minded guru did not mesh with the Steelers identity
The other internal option in Pittsburgh was Ken Whisenhunt, the offensive coordinator of the Steelers. He held that title for two years and it seemed like his future would either be etched with the black and gold or elsewhere as a head coach. He was an offensive minded guru that was able to help create one of the better offenses in the league.
Another thing that worked in his favor was his age of 45 years old at the time, just like Rivera. He had a lot of experience, and many wondered if the club would turn more towards the offensive side of the ball with a young Ben Roethlisberger becoming the main act. Even though Whisenhunt was one of the finalists for the job, he never got the job with the Steelers.
He would join the Arizona Cardinals as their top guy with the club and both he and Tomlin would go head-to-head in Super Bowl 43. Tomlin and the Steelers won that game and that seemed to justify that move of hiring Tomlin over Whisenhunt at the time. Unfortunately for him, time only made things worse for his career as a head coach in the NFL.
Whisenhunt only lasted in the desert for five seasons before both parties went their separate ways. He would get other chances to coach elsewhere, but he would not last long in those positions. Tomlin was the best hire of that crop of coaches back in 2007 and even to this day. He might not be a perfect coach in the NFL, but he has been a successful one.