Size is indeed, IMO, an important factor in evaluating a QB.
Foot speed,yes.
Strong accurate passer,yes
Quick/smart mind,yes.
Good/great college film history,yes
Ryan Fitzpatrick :
Smart (Harvard U.)
Game skills,yes
Can lead a teams offense successfully,yes
A tough "football player", yes.
A franchise GB, no way. However most teams would be happy to hire him as their #2 QB.
Fitzpatrick has proved himself a capable journeyman "backup" QB, but he has always lacked that "it" intangible that can't be found through statistical analysis. Favre had "it", Payton Manning had "it", Brady and Rodgers have "it". "It" is what places them on a higher level above the others. Finding the"it" factor may be the most difficult part of the scouting process.