Outfield defense. I know carrying extra pitchers limits the bench to a few multi-positional men, but having one above-average glove for late-innings in the outfield could have helped secure more wins.
Cordero and Renfroe are below-average MLB hitters, but at least Renfroe can field his position. Franchy's MLB career may be a small sample size, but he can't be trusted in left. He's faster than JD -- so are most posters here -- but no way either should be on the field when it matters. Verdugo, Kike and Renfroe are the best for now and should close most games.