Second this. There's an enormous difference between a 2nd-string QB and an "uh-oh, put on your helmet, quick!" QB.
As for McCoy and Fitzpatrick, they're not chopped liver and they have a lot in common. Not the biggest, most impressive athletes; not the strongest arms. But they're generally smart, patient, accurate quarterbacks who take what you give them and don't make stupid mistakes. IOW, "game managers" -- a term that's often used dismissively, but I take it as a complement. And it seems to me that the game manager type is the type BB has the most trouble with.
I can't claim to be a Matt Flynn expert, but I notice that in his pre-draft profile, nfldraftscout.com said the best NFL comparison was...Ryan Fitzpatrick. (And he even has the classic Irish surname to match Fitzpatrick and McCoy.)