Corky Miller is not Ryan Hanigan behind the plate. Corky is a journeyman catch who can't hit. Hannigan is an elite catcher- in the same class with Jerry Grote and Joe Gerardi when it comes to handling a pitching staff and running a game. Sure offense is nice, but when it comes to winning, how you handle things behind the plate is what counts. Hannigan is special, whether he his .280 or .230.
PS. Mike Piazzi was a great hitter who happened to catch. Behind the plate, you can't mention him in the same sentence with Hanigan. In any event, Mesoraco is not Piazza when it comes to hitting a ball so there's no decision to be made there.