I'm not sure the best way to judge non-throwing defense. I'm definitely not a fan of C-ERA.
His FPCT was above average. His Range Factor was average (and above each of the 3 with better CS%).
I agree he's no Johnny Bench back there. However, I'm not sure I've seen evidence that he's worse than average defensively and he has one of the best arms in the league. Outside of anecdote, do you have reason to think he's bad? Scouting report, some other metrics, etc.? I'm actually curious -- catching defense is even tougher than everybody else's to judge.