That perspective discounts the importance of quarterback play in the National Football League.
As strongly as quarterback play is related to winning in this league, you can't have a quarterback who is performing below average on just about every objective measure and call him "the least of your problems."
Until you have a quarterback who is performing at least above average, he is your biggest problem, because until you get that issue sorted out, you will very likely not be competitive in this league.
When your team is mediocre, and your quarterback is playing significantly better than the rest of the team, I'd say he is the least of the problems. In other words, if you put an overall average product around him, you would be able to expect at minimum, above average play.