Timing has always been an element of what we implemented into our system and you would be surprised on some of the offenses that still rely heavily on timing. But that's another discussion that talks about actual QB skill vs reliance on skill players that meant for another day . Diagnosing a defense comes from film study and knowing how to manipulate this comes from understand the playbook. But it seems like a lot of people are mistaking what I'm saying. I'm not saying that the system teaches someone how to play QB nor saying that the system replaces football IQ but I'm saying that the greatest QBs in the league have the vast experience in a single system as a common denominator.
Also, your point about Manziel slightly misses the mark because he just did what he wanted to in college and it just worked but I remember Merrill Hodges said that it was nothing on film that would make him take him as an NFL QB..lol. And if you pay attention to the QB position now, most are pulling elements from college into the league to help the QB. This is part of the development that Tom Brady was talking about.
Manning had elite field vision, but he also turned he ball over at a much higher rate than most in the league for a good bit of time.