If we were the Lions, you could say you would be excited by the hire?
Caldwell is an average coach. If he was a GREAT coach, do you think Irsay would've fired him after purposely tanking? Caldwell benefited from having the greatest QB of all-time and inheriting an already constructed and established winning team.
And the Ravens offense didnt change a lot other than Caldwell sitting back and letting Flacco have more say in what the philosophy and calls would be, IIRC. The problem was Cameron was having a power struggle and ego battle with Flacco, so they fired him and brought in Caldwell to get back to what they were doing before the issues came up with Cameron (aka more Rice, with some deep shots sprinkled in). That's not to say that Caldwell isn't a good coordinator, he just hasn't proven to be a good head coach to this point, and Stafford is no Peyton Manning... maybe not even a Flacco. So, he has his work cut out for him.
Not saying Caldwell is or is not a good coach, but Jim Irsay isn't exactly the sharpest tool in the shed.