That's valid, but (as you acknowledged) we knew that before he was signed, so if it was gonna be this big of an issue, the signing shouldn't have happened.
IMO, his pluses far outweigh those negatives, although I understand why people get so frustrated by them. However, what I don't get is the idea that McCann is some polar opposite. He was at the top of the league in catcher's interference errors and, like Grandal, also dropped a routine pop-up.