You know...I am completely sure I'm in the minority here, but I've found catcher defensive ratings across the board to be wildly overrated...you hear about all of "those teams," where the owner likes to steal bases, but I don't find them to be any more or less successful as a team against any of my squads. I've played worse catchers than that against teams like that, and won series'....
In Moonlight Graham, just this past offseason, I played a team like that, Little Rock, that had 2 guys over 100 steals, a third in the 90s and a fourth in the seventies (IIRC).
I put my all-star D-type catcher out there, and they went 13-15 against me in the first four games until I benched the guy and put in his FAR less superior, better offensive option in the game.
Granted, in that last game, they went 3-for-3 stealing bases. But we won the game by 8 runs.
ANYWAY...long story short, the reason that I think that the defensive ratings are overrated is because the stolen base just doesn't mean much in this game. Truly.