(1) Detroit's problems in the bullpen weren't closer-centric. The whole bullpen had problems.
(2) I don't drink the Moneyball-flavored kool-aid. Average closers are fungible. Elite closers are not. Bill James used to deconstruct saves into different categories of difficulty and I'd be curious to see what the difficulty rating for Kimbrel's saves has been since he's closed for us. Former Twins' manager Tom Kelly used to talk about the psychological value of an elite closer and how an erratic closer (and other elements of a bad bullpen) erode a team's confidence. One can't measure that and in an era where data is king, queen, and the entire court, that angle is often downplayed. The Braves' margin for error isn't that great (at least it isn't in my view), which may make Kimbrel more valuable to us than to others.
(3) If someone deems Kimbrel the next Mariano, there will be a market for him. I just don't want to see Millwood redux, where Kimbrel is shed primarily for budget purposes.
(4) All this said, I wouldn't be surprised if Kimbrel is moved.