I'm reminded of the old Henny Youngman joke: "How's your wife?" "Compared to what?"
Tomlin has his flaws, but he's one of the better coaches in the league, and statistically speaking, it is unlikely his replacement would be better. As for the argument "What they're doing isn't working; they need to try something else," well, that's simply not how the Steelers have operated over the past 50 years. And given that they have been the most consistently successful franchise in the league over that timeframe, I'm inclined to think they may be on to something. In fact, I think more teams should approach their coaching situations like the Steelers, not the other way around.