I think its much harder to rank 9-20 or so than it is 1-8. If you don't have some sort of order between Rodgers, Brady, Gomer, Cletus, Brees, Roethlisberger, Flacco, and Ryan in your Top 8, you suck at watching football. 9-20 is where it gets murky and tough to rank guys. It really comes down to your homerism, preference, or how you project the young guys.
You got the stat compilers like Tony Romo, Matt Stafford, and Phillip Rivers. You got the young guys like Andrew Luck, Colin Kaepernick, Robert Griffin, Cam Newton and Russell Wilson. Then you got then underrated guys like Andy Dalton and Matt Schaub who just get their teams to the playoffs.