This year they also added an actual threat across from Calvin Johnson, had improved play from young players on the defense like Darius Slay and Ziggy Ansah and added an actual good safety next to Glover Quin. Schwartz would have taken the same roster to the playoffs just like Caldwell did.
IIRC they also had some injury issues last season especially at the WR position which effectively neutered the offense for a good portion of the season