Maybe you view him as boring, but he's successful, once again coaching a top defense and getting results, which is what is most important.
He was a HC for 3 full seasons, went from 3-13 to 10-6 and a playoff berth then back down out of the playoffs year 3. I wouldn't say he failed. He also made the playoffs with Christian Ponder as his QB, and got fired the year after Ponder, Matt Cassell and Josh Freeman were his QB's. Seems like the GM failed more than Frazier
Obviously, I'm a Frazier fan, have been since his days with the Vikings. He's a damn good coach.