While I absolutely don't deny that he leaves plays on the field, as you say, again if there is no point of comparison, what is the purpose of brining it up? What if you analyzed every single starting QB in the NFL and broke down their plays and it turned out that Tyrod in reality was within the top 15-20 QB's in the league at leaving the fewest plays on the field? What if Tyrod was in the top 5 in reality at leaving the fewest plays on the field? Maybe Tyrod would be ranked 32nd in the NFL at leaving fewest plays on the field.
My point is, b/c you have absolutely no point of comparison for your statement that he leaves plays on the field, the entire exercise is jaded and pointless b/c in reality the few plays he leaves on the field may actually be better than 50% of the QBs in the league (or it may not be).
In essence, you're building a "cautionary tale" about something for which you have no sensible idea if it requires caution or not.