That the middle of the pack was a whole HELL of a lot better than what we thought we'd get out of the catcher's position at the start of the year. Heck it was what we were HOPING to get. If Salty had been an unmixed blessing this year, that would have frankly been incredible fortune.
The fact that he was somewhat above that at the middle of the season and then fell back changes nothing. Salty progressed this year, both offensively and especially defensively, and is a creditable average catcher with a mix of skills and weaknesses. Considering where he was at the start of the year, that's pretty significant. Let's not forget that we picked this guy up virtually off the scrap heap.
I wouldn't call him defensively weak. He has strengthes and weaknesses behind the plate. Salty had a good year throwing out baserunners. He keeps throwing out baserunners at a 30% clip, teams are going to start respecting that arm more. And remember- -- Salty was the guy who handled Wakefield this year, that affects both how often players run on him, and his passed ball numbers, which led the league. And as a pitchcaller, well, he isn't Tek, but nobody's Tek. Salty's alright there.
According to WAR you're getting average production on both sides of the ball -- a little better than with the bat, a little worse than with the glove -- but remember that WAR doesn't cover the Wakefield Effect. Since we probably will not bring Wake back next year, I'd expect Salty's numbers to improve across the board defensively regardless.