Generally, when a coordinator steps down from their position, it is not a good thing. Stepping down generally means retirement or they've been offered a better job somewhere else, and are leaving whatever team they discarded searching blindly for a new playbook and ideas. The team can wander in anonymity for a few years before they find an offense/defense that clicks, and that is a depressing thing to watch as a fan.
None of this applies to the Pittsburgh Steelers as Bruce Arians, the now-former offensive coordinator, has stepped down from his position. Arians leaves the Steelers as someone who attempted to single-handedly cripple the offense from the inside, as if the Baltimore Ravens had planted a double agent within the Steelers organization. Arians is famous for two things:
1. The bubble screen, which to the best of my knowledge, worked seven times over a course of four years. This play was tried at least 200 times over this period, in spite of whatever coverage was set in front of the Steelers. Every failure ended with the defensive back cutting out Hines Ward/Mike Wallace's legs from under them, almost causing a torn ACL every damn time.
They should call this play the "Arians," because only the Virgin Mary is more synonymous with an inane random play. It never worked, and I am ecstatic to see it retire with Arians.
2. The first-down run—gain of two. This was a regular thing during the Arians era, as creativity with the offense was never his strong suit. If the Steelers ever tried anything daring, it was either Ben Roethlisberger's call, or because Ben had scrambled in the pocket 15 seconds too long. This play was monotonous and dull, because every running back the Steelers have ever had immediately runs into the back of the offensive lineman when running up the middle.
These two plays were Arians in a nutshell—cautious and consistent, a style that made no sense given the talent of the various skill players the Steelers had during the time period. Fans have been clamoring for his exit for eons, it seemed, and I'm sure the city of Pittsburgh is doing everything it can to stop a city-wide celebration from happening.
There's a rumor that has circulated around Pittsburgh that two years ago, Mendenhall did every sadistic Steelers fan dream and punched Arians in the face. This is obviously an Internet rumor, and therefore likely false, but I still ogle at the idea that Mendenhall possibly finds more merit in Osama bin Laden than he did with Arians.
As for what I said in the beginning—the whole "wandering around for a new playbook" thing—the Steelers with whomever they hire should feel relieved to have new plays. This shouldn't be a big deal for them as it would be with other teams.
Arians is retiring to graze the pasture, or whatever it is that retired football coaches do. Either way, it is time for a change in Pittsburgh. The offense was handicapped by conservatism, something that drew me and a lot of other Steelers fans insane over the past four years. I'm exhausted.
Bruce, good luck in whatever it is you plan to do with your free time.