The problem I had with Mario Impemba was his inability to provide any actual baseball insights during the broadcast.
Everything Mario said about the actual game in progress was either a basic description of the pitch or play that just happened; a reciting of the batting or pitching line the player had achieved during the game to that point; or a snippet from the media notes about the team or the player in question. Practically everything else Mario said during the broadcast was either a live read promotion, a throw to the field or studio announcers, or a forced attempt at banter.
I didn't fault Mario for the live reads or throws or even the attempted banter, but the bare bones description-only nature of his game commentary was where he really lacked. Mario apparently neither talked to the players, as Jim Price or Rod Allen did, nor dug into the numbers, like Dan does, which leaves only a dry recitation of what he saw in front of him or read from his notes.
Mario was a perfectly competent announcer, technically, but I got no sense that he was at all engaged with the game going on in front of him.