That’s a good question. I’ve believed for years that the parts of a QB’s game that are undervalued are leadership, how well they play under pressure, what kind of team they were surrounded by. I believe both scouts and fans are over enamored with arm strength and athleticism and fail to see a college QB in context of the team they played for and how his play impacted that team.
For example, too many college QBs drafted early have been overvalued because of the team they play for. I always thought Tua was good, but he was constantly surrounded by NFL talent on those Alabama teams making him look a little better than he is. Contrast that with Mahomes, who because I’m a Texas Tech fan, I saw him play every game in college- he was great while being surrounded by almost zero NFL talent on below average Tech teams.
One thing that really helps college QBs get ready for the pros is simply experience as a starter. Look at Dwayne Haskins. Dude started like 15 games in college before being drafted in first round. Contrast that with guys like Mahomes, Justin Herbert, Baker Mayfield and Russell Wilson all started between 35 and 45 games in college. That makes a huge difference in being prepared to play in the NFL.
The reason I mention pressure- look at how QBs play under duress. Guys like Tua, Matt Jones and Trevor Lawrence rarely got pressured in college like they will in the NFL. Last year as a rookie, Justin Herbert was off the charts accurate under pressure. He showed that in college too. It’s easy to look great when no one is in your grill.
Finally, the leadership quality. Some QBs just have a special quality that cannot be tape measured. Joe Montana, Roger Staubach, Tom Brady, and Johnny Unitas all had this aura about them that lifted the whole team’s play. They are seemingly in every game because of their ability to lead a comeback against the odds. They are special in an intangible way.
In this current era of QBs, I think too many teams just don’t do their homework on the more subtle parts of what makes a great QB.