I've never seen a coach with as little emotion as Caldwell.
I have. Bill Belichick.
I don't think it's time to fire Caldwell. This team has all the talent of a 5-11 team, yet they went 9-7 and made the playoffs. They way over achieved. Caldwell isn't the best, but for where the Lions are right now he will do. If they ever get some real talent he'll need to be replaced as I don't think he's the guy to take them to the next level. At least keep him through next season while Quinn keeps building.
He did make some terrible game managing and clock managing decisions this season that hurt them.