Comparing the role of closer to any other position doesn't really work.
The stats crowd gets mad when you point to the save statistic, but the save statistic is all that matters when your job is to come in and get a save.
Based on what we've seen from Martinez lately, he's playing with fire. He's also getting the job done. When he can't, make the change. If ever there was a spot for a pass/fail evaluation, it's with a closer.
The Cardinals have seven wins post-Hicks because Carlos did his job.. Was it always pretty? No. Was it always easy? No. Does it matter? No.
As for Carpenter, I'm not beating the table for him to start right away. The Cardinals have a good thing going with the young guys. Shildt is in for another interesting challenge when it comes to how he handles this. If he starts Carpenter immediately, and Carpenter looks like the same version of the guy we saw all season, that's not conducive to winning.