Go back thru all the Super Bowls and I think you'll find that the by-the-book, system-type classic QB, with but a couple of outlier exceptions, wins. The more exciting pull-it-out-of-your butt "gunslinger" QBs get the fan mania but tend not to get the brass ring. Two of that type - Tarkenton and Kelly -- alone count for 8 losses and no SB wins. Compare Stabler & LaMonica with Bradshaw in the 70s, or think of Favre, the ultimate gunslinger who, for all the raves, managed one SB win in an era that overlapped with the dull Troy Aikman and the highly "system" QB John Elway.
What's winning me over with Josh Allen is his growing competence as a system QB who retains some fine gunslinger ability. That just might be the secret sauce for major success.