I agree, AJ Green or Patrick Peterson's Wonderlic matters very little to almost nothing. Though it does make you wonder how they the necessary SAT scores to get into college if they don't test well. But I think there's definitely some strong evidence to show that it matters with quarterbacks. This article does a pretty good job of laying it out -
A Formula For Drafting QBs That Works: Rule of 26-27-60 - Hogs Haven
And re: Bradshaw, Kelly, Cunningham, etc
My guess is that the Wonderlic wasn't generally perceived to matter in those days, so when stud qb's like Marino and Bradshaw got presented with a bubble test, they probably didn't pay it much attention. These days it matters, and preparing for the Wonderlic as a qb is now a part of the draft preparation, including tutors and practice sessions. Much worse to score low on a test you've prepared for and that you know is important than when you don't think it matters.