I won't insult your intelligence by listing the highly rated QBs that just didn't do well for whatever reason. We recruited several that other blue-chip programs desperately wanted: it's a crap shoot with QBs, especially, since there are so many different skill factors. You do understand that top NFL QBs aren't necessarily the collegiate stars? Well, same holds for high school. I find that's a part of what makes following this sport so intriguing.
Frankly, I don't know why you think Vernon Adams wasn't a grand positive: his stats very favorably compare with MM's; actually, Vernon would get the nod from me to start over MM: he was a better long ball player and he had enough "quicks" to keep defenses honest. Also, he didn't have MM's penchant for fumbling when hit and for blowing a lot of plays in the beginning of games.