Every QB has flaws. Every QB has strengths. Sometimes the only thing that separates an elite QB from an average QB are intangibles. I have never seen Tannehill go for a free play after a hardcount. Rodgers and Tannehill could have the exact same arm talent but the guy doing the little extras, like the free play, and the pocket manipulation, and noticing when its a 3 man rush, and getting to the line quick when the defense is making changes is going to increase his teams chances.
Well, until last season, he wasn't allowed to change plays.