A few things...I would turned Ireland and Sparano out after the 2010 season. So, if I was the owner, he would have been gone a long time ago.
With that said, I am tired of people thinking the answer is canning the GM. After the Pats game in Week 15, everyone thought this was a playoff bound team. The players were good enough to make the playoffs and up end the Pats. Yet, after two clunkers to finish, the players are not good enough? Sorry, the last two weeks was on coaching, starting with the guy at the top.
If you can the GM, then allow the new one select his new coach...one with the same vision.
BTW, I am saying you keep him and his staff through the draft and after start transitioning people out....it is at least a method of transition.